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From the Department of Clinical Neuroscience
Karolinska Institutet, Stockholm, Sweden
LINKS BETWEEN STRESS, SLEEP, AND
INFLAMMATION: A TRANSLATIONAL
PERSPECTIVE OF RESILIENCE
Heather L Rusch
Stockholm 2020
All previously published papers were reproduced with permission from the publisher.
Published by Karolinska Institutet.
Printed by Universitetsservice US AB.
© Heather L Rusch 2020
ISBN 978-91-7831-953-4
LINKS BETWEEN STRESS, SLEEP, AND
INFLAMMATION: A TRANSLATIONAL PERSPECTIVE
OF RESILIENCE
THESIS FOR DOCTORAL DEGREE (Ph.D.)
By
Heather L Rusch
Principal Supervisor:
Dr. Julie Lasselin
Karolinska Institutet
Department of Clinical Neuroscience
Co-supervisors:
Prof. Mats Lekander
Karolinska Institutet
Department of Clinical Neuroscience
Dr. Jessica M Gill
National Institutes of Health
National Institute of Nursing Research
Brain Injury Unit
Opponent:
Prof. Nicolas Rohleder
University of Erlangen-Nüremberg
Department of Psychology and Sport Science
Examination Board:
Dr. Christian Benedict
Uppsala University
Department of Neuroscience
Prof. Sophie Erhardt
Karolinska Institutet
Department of Physiology and Pharmacology
Prof. David Mataix-Cols
Karolinska Institutet
Department of Clinical Neuroscience
A waxing gibbous moon illuminates the tortuous trail as mountaineers climb up Adam’s
glacier, towards the summit of Mt Adams, in the Cascade Range, Washington. The moon, a
reminder that this journey is a passing phase.
― Photo by Joseph K Sabek
Whatever road I take I’m going home…
Heather L Rusch
II
ABSTRACT
Most individuals will experience one or more extremely traumatic events during their
lifetime. For the most part, humans are resilient and have a tremendous capacity to bounce
back from hardships; however, for a critical minority, trauma can result in debilitating
symptoms, including posttraumatic stress disorder (PTSD). Historically, sleep disturbance
and inflammation were viewed as symptoms or consequences of PTSD; however, recently
there has been a shift towards conceptualizing sleep disturbance and inflammation as early
indications of mental health issues to come. This thesis examined the inextricable link
between stress, sleep, and inflammation, and how gaining a better understanding of these
interconnected systems could be harnessed to develop enhanced treatments for populations
with stress-related symptoms and disorders.
Study I investigated the effect of standardized sleep therapy on posttraumatic stress
symptoms, as well as the gene expression pathways that may mediate this effect in sleep
disturbed military service members with PTSD (n =39) and controls without PTSD (n =
27). At baseline, participants diagnosed with insomnia and/or obstructive sleep apnea
received a combination of 4 to 8 biweekly sessions of cognitive behavioral therapy for
insomnia (CBT-I), and automatic positive airway pressure therapy. Results indicated that
22.6% of participants with PTSD had clinically meaningful posttraumatic stress symptom
reduction following standardized sleep therapy. Posttraumatic stress symptoms were linked
to increased expression of genes associated with immune response systems, which were
downregulated with symptom reduction at follow-up.
In order to investigate alternative interventions that may improve sleep quality and
potentially provide additional benefits for stress-related disorders, Study II was a meta-
analysis to determine the effect of mindfulness meditation on sleep quality outcomes in
sleep disturbed adults with various mental and physical health conditions. To assess for
relative efficacy, mindfulness meditation was compared to evidence-based sleep treatments
(like CBT-I and medication) and time/attention-matched interventions to control for
placebo effects, which were analyzed separately. The results indicated that mindfulness
meditation had a similar effect on sleep quality compared to the evidence-based sleep
treatments and was superior to the time/attention matched placebo controls. However, the
strength of this evidence was low to moderate, so some doubt remains.
Stress, Sleep, and Inflammation
III
Once mindfulness meditation was established as a potential intervention to improve sleep
quality, Study III investigated if sleep quality improvements, following a 4-week
mindfulness-based integrative medicine program, were associated with reductions in
posttraumatic stress, anxiety, depression, and postconcussion symptoms in sleep disturbed
military service members with mild traumatic brain injury (n = 93). The secondary aim was
to determine if sleep quality improvements were associated with decreases in protein levels
of inflammation. Results indicated that sleep quality improvements, following the
intervention, were linked to reductions in posttraumatic stress and other neurobehavioral
symptoms, but not to inflammation. Moreover, 65.8% of participants with PTSD had
clinically meaningful posttraumatic stress symptom reduction at follow-up.
While we found some evidence that posttraumatic stress symptoms were reduced following
the mindfulness-based integrative medicine program, this program required almost 30
treatment hours. This may be an excessive treatment duration when mindfulness meditation
is used in populations with less severe symptoms. As such, Study IV investigated the effect
of a brief 5-week (7.5-hour) mindfulness meditation program on perceived stress symptoms
in moderately stressed healthcare professionals. Participants were randomized to the
mindfulness-based self-care (MBSC) group (n = 43) or the life-as-usual control group (n =
35). Results indicated that the meditation group had larger reductions in perceived stress,
and these reductions were maintained two months following the completion of the program.
Taken together, the findings of these four studies led to some important conclusions
regarding the link between stress, sleep, and inflammation. While mindfulness research is
still in its infancy, these preliminary results suggest that mindfulness meditation is effective
in improving sleep in adult populations with various mental and physical health conditions
(Study II). Less intense mindfulness meditation programs (7.5 hours) may be beneficial to
reduce perceived stress, which could potentially prevent the development of more severe
mental health conditions (Study IV). While 22.6% of individuals with PTSD had reduced
posttraumatic stress symptoms following standardized sleep therapy (Study I), 65.8% of
individuals with PTSD had reduced posttraumatic stress symptoms following the
mindfulness-based integrative medicine program (Study III). There was some evidence
that a relationship exists between sleep quality improvements, decreases in gene expression
levels of inflammation, and reductions in posttraumatic stress symptoms; although the
direction of causality cannot be determined (Study I and III). Clinical implications and
recommendations for future research will be discussed.
Heather L Rusch
IV
LIST OF INCLUDED SCIENTIFIC PAPERS
STUDY I
Rusch, H. L., Robinson, J., Yun, S., Osier, N. D., Brewin, C. R., &
Gill, J. M. (2019). Gene expression differences in PTSD are uniquely
related to the intrusion symptom cluster: a transcriptome-wide analysis
in military service members. Brain, Behavior, and Immunity, 80, 904-
908.
STUDY II
Rusch, H. L., Rosario, M., Levison, L. M., Olivera, A., Livingston,
W. S., Wu, T., & Gill, J. M. (2018). The effect of mindfulness
meditation on sleep quality: a systematic review and meta-analysis of
randomized controlled trials. Annals of the New York Academy of
Sciences, 1445(1), 5-16.
STUDY III
Rusch, H. L., Jiang, A., Guedes, V. A., Haight, T., Lekander, M., Gill,
J. M., DeGraba, T.,* & Lasselin, J.,* (2020). Associations between
sleep quality, neurobehavioral symptoms, and inflammation among
combat-exposed military service members: an observational
integrative medicine study. (*contributed equally) Manuscript.
STUDY IV
Ameli, R., Sinaii, N., Luna, M. J., Panahi, S., Zoosman, M., Rusch, H.
L., & Berger, A. (2020). The effects of a brief mindfulness-based
program on stress in healthcare professionals in a biomedical research
institution: a randomized controlled trial. JAMA Network Open, 3(8),
1-12.
Stress, Sleep, and Inflammation
V
LIST OF RELATED SCIENTIFIC PAPERS
Related scientific papers (denoted with Arabic numerals) are not included in this thesis but
are discussed in relation to the current body of work.
PAPER 1
Rusch, H. L., Guardado, P. A., Baxter, T., Mysliwiec, V., & Gill, J.
M. (2015). Improved sleep quality is associated with reductions in
depression and PTSD arousal symptoms, as well as increases in IGF-1
concentrations. Journal of Clinical Sleep Medicine, 11(6), 615-623.
PAPER 2
Livingston, W. S., Rusch, H. L., Nersesian, P. V., Baxter, T.,
Mysliwiec, V., & Gill, J. M. (2015). Improved sleep in military
personnel is associated with changes in the expression of
inflammatory genes. Frontiers of Psychiatry, 6(59), 1-15.
PAPER 3
Guardado, P. A., Olivera, A., Rusch, H. L., Roy, M. J., Martin, C. G.,
Lejbman, N., Lee, H., & Gill, J. M. (2016). Altered gene expression of
the innate immune, neuroendocrine, and NF-κB systems is associated
with posttraumatic stress disorder in military personnel. Journal of
Anxiety Disorders, 38, 9-20.
PAPER 4
Goyal, M. & Rusch, H. L. (2019). Mindfulness-based interventions in
the treatment of physical conditions. In Farias, M., Brazier, D., &
Lalljee, M. (Eds.), The Oxford handbook of meditation. Oxford, U.K.:
Oxford University Press.
PAPER 5
Guedes, V., Lai, C., Devoto, C., Edwards, K., Qu, B., Rusch, H. L.,
Mithani, S., Acott, J. D., Martin, C., Wilde, E. A., Walker, W. C.,
Diaz-Arrastia, R., Gill, J. M., & Kenney, K. (2020). Exosomal
miRNAs and proteins are linked to chronic posttraumatic stress
disorder symptoms in service members and veterans. In Press.
Heather L Rusch
VI
CONTENTS
1 INTRODUCTION ......................................................................................................... 1
1.1 Stress .................................................................................................................... 1
1.1.1 Effects of acute stress .............................................................................. 2
1.1.2 Effects of chronic stress ........................................................................... 2
1.2 Posttraumatic Stress Disorder .............................................................................. 4
1.2.1 Diagnostic features .................................................................................. 4
1.2.2 Diagnostic discrepancies ......................................................................... 4
1.2.3 Prevalence ................................................................................................ 5
1.2.4 Comorbidities ........................................................................................... 7
1.3 Sleep ..................................................................................................................... 7
1.3.1 Stages of sleep .......................................................................................... 8
1.3.2 Measurements of sleep ............................................................................ 9
1.3.3 Link between sleep and posttraumatic stress .......................................... 9
1.4 Inflammation ...................................................................................................... 10
1.4.1 Measurements of inflammation ............................................................. 11
1.4.2 Link between inflammation and posttraumatic stress ........................... 13
1.4.3 Link between inflammation and sleep ................................................... 13
1.5 Thesis Rationale ................................................................................................. 14
1.5.1 Link between stress, sleep, and inflammation ....................................... 15
1.5.2 Sleep-focused treatments ....................................................................... 16
1.5.3 Mindfulness meditation programs ......................................................... 16
1.5.4 Integrative medicine programs .............................................................. 17
2 STUDY AIMS ............................................................................................................. 19
3 METHODS .................................................................................................................. 21
3.1 Study I: Methods ................................................................................................ 22
3.2 Study II: Methods .............................................................................................. 23
3.3 Study III: Methods ............................................................................................. 25
3.4 Study IV: Methods ............................................................................................. 27
4 RESULTS .................................................................................................................... 29
4.1 Study I: Results .................................................................................................. 30
4.2 Study II: Results ................................................................................................. 32
4.3 Study III: Results ............................................................................................... 34
4.4 Study IV: Results ............................................................................................... 36
5 DISCUSSION .............................................................................................................. 39
5.1 Study I: Discussion ............................................................................................ 39
Stress, Sleep, and Inflammation
VII
5.2 Study II: Discussion ........................................................................................... 41
5.3 Study III: Discussion .......................................................................................... 41
5.4 Study IV: Discussion .......................................................................................... 42
5.5 General Methodological Considerations ........................................................... 44
5.6 Clinical Implications & Future Directions ........................................................ 46
6 CONCLUSIONS ......................................................................................................... 49
7 ACKNOWLEDGEMENTS ........................................................................................ 51
8 REFFERENCES .......................................................................................................... 55
9 APPENDIX .................................................................................................................. 75
Heather L Rusch
VIII
LIST OF ABBREVIATIONS
ACTH
Adrenocorticotropin
ANOVA
Analysis of variance
APAP
Automatic positive airway pressure
BMI
Body mass index
CBT-I
Cognitive behavioral therapy for insomnia
CRH
Corticotropin-releasing hormone
CRP
C-reactive protein
DNA
Deoxyribonucleic acid
DSM
Diagnostic and Statistical Manual of Mental Disorder
Dx
Diagnosis
GAD-7
General Anxiety Disorder 7-Item
GLMM
Generalized linear mixed models
HEP
Health Enhancement Program
HPA
Hypothalamic-pituitary-adrenal
ICD
International Classification of Diseases
IFNγ
Interferon gamma
IL
Interleukin
ISI
Insomnia Severity Index
IVT
In vitro
MAAS-S
Mindful Attention Awareness Scale—State
MAAS-T
Mindful Attention Awareness Scale—Trait
MBCT
Mindfulness-based cognitive therapy
MBI-2
Maslach Burnout Inventory 2-Item
MBSC
Mindfulness-based self-care
MBSR
Mindfulness-based stress reduction
MCID
Minimal clinically important difference
MOS-SS
Medical Outcomes Study—Sleep Scale
mRNA
Messenger ribonucleic acid
MSCS-G
Mindful Self-Care Scale—General
Stress, Sleep, and Inflammation
IX
mTBI
Mild traumatic brain injury
NF-κB
Nuclear factor kappa light chain enhancer of activated B cells
NK
Natural killer
NREM
Non-rapid eye movement
NSI-22
Neurobehavioral Symptom Inventory 22-Item
OSU TBI-ID
Ohio State University, Traumatic Brain Injury Identification Method
PANAS
Positive and Negative Affect Schedule
PCL-M
PTSD Checklist—Military Version
PHQ-9
Patient Health Questionnaire 9-Item
PSQI
Pittsburgh Sleep Quality Index
PSS-10
Perceived Stress Scale 10-Item
PTSD
Posttraumatic stress disorder
REM
Rapid eye movement
RNA
Ribonucleic acid
SAM
Sympathetic–adrenal–medullary
SIMOA
Single Molecule Array HD-1 Analyzer
SWS
Slow-wave sleep
TNF
Tumor necrosis factor
VAS-A
Visual Analog Scale—Anxiety
Heather L Rusch
X
Let what comes come.
Let what goes go.
Find out what remains.
― Ramana Maharshi
Stress, Sleep, and Inflammation
1
1 INTRODUCTION
Pain and suffering are inextricable experiences of the human condition. Most individuals
will experience one or more extremely traumatic events during their lifetime; however,
there is significant variability that governs subsequent responses to these events.1 For the
most part, humans are resilient and have a tremendous capacity to bounce back from
hardships.2 However, for a critical minority, trauma can result in debilitating symptoms that
impact multiple dimensions of functioning and quality of life.3 What explains these
differences and how can these symptoms best be treated, or better yet be prevented? The
answer is only partly understood, but burgeoning evidence points to sleep and inflammation
as key players in the pathogenesis and maintenance of stress-related disorders.
1.1 STRESS
In 1950, Hans Selye first defined stress from a biological perspective as a nonspecific
response of the body to any demand made upon it (e.g., exercise, extreme temperatures).4
Not all scientists agreed with Selye’s definition; they argued that if the stress response was
nonspecific then everyone should react the same way to the same stressor.5 In the 1960s,
cognitive processes were integrated into the biological model of stress to resolve this
discrepancy. It was determined that individual differences in perception account for these
diverse responses to a stressor—stress is not what happens to you, but how you respond to
it.6 Despite this reconciliation, there are a number of universal conditions that elicit a stress
response in almost everyone: novelty, unpredictability, and loss of control.7 The terms
eustress (i.e., good stress) and distress (i.e., toxic stress) were later introduced to distinguish
the stress response triggered by a positive event from a negative event (Figure 1).8,9
Figure 1 | The human function curve. Eustress improves performance, creativity, and growth.
Meanwhile, distress causes fatigue and exhaustion followed by the onset of mental and physical
health conditions, which impede performance. Adapted from “The human function curve: a
paradigm for our times”, by P.G. Nixon, 1982, Activitas Nervosa Superior, p. 133.
Comfort Zone
Low stress High stress
Low performance High performance
Hypostress Distress
Eustress
Peak
Output
Boredom
Dissatisfaction
Fatigue
Exhaustion
Mental &
Physical Health
Conditions
Burnout
Breakdown
Heather L Rusch
2
1.1.1 Effects of acute stress
When an event is perceived as a stressor, the brain and body recruit a range of complex
systems to maintain homeostasis.10 This adaptive stress response is called allostasis—
achieving stability through change.11 The first phase of the stress response is initiated by the
central nervous system, whereby physical stressors (e.g., viral infections) are mainly
processed by the brainstem and limbic regions, and psychosocial stressors (e.g., public
speaking) are largely processed by the executive, affective, and salience networks,
including the prefrontal cortex, amygdala, and hippocampus.12-14 Next, the autonomic
nervous system is activated, namely, the sympathetic–adrenal–medullary (SAM) axis,
which culminates in the release of epinephrine and norepinephrine (collectively
catecholamines) into the bloodstream by the adrenal medulla.15 Then the hypothalamic-
pituitary-adrenal (HPA) axis is activated, in which corticotropin-releasing hormone (CRH)
is secreted from the paraventricular nucleus in the hypothalamus.16 This elicits the secretion
of adrenocorticotropic hormone (ACTH) from the anterior pituitary gland, prompting the
synthesis and release of glucocorticoids (cortisol in humans) into the bloodstream by the
adrenal cortex.16!The increase of circulating catecholamines and glucocorticoids coordinates
widespread changes in vast systems (e.g., immune, cardiovascular, metabolic) to protect
and prepare the body for a fight-or-flight response.17 Once the perceived stressor has
passed, feedback loops are triggered in various systems (e.g., from the adrenal gland to the
hypothalamus) to terminate the stress response and restore homeostasis.18
1.1.2 Effects of chronic stress
When the stress response becomes prolonged or excessive, it can put wear and tear on the
brain and body (i.e., allostatic overload) and cause alterations in physical, cognitive,
emotional, and behavioral functioning (Figure 2).19 Within the immune system, a persistent
influx in glucocorticoids may result in glucocorticoid receptor resistance, which in turn,
interferes with the downregulation of inflammation.20 The combination of HPA axis
dysregulation and increased inflammation might converge with other brain and body
systems to contribute to psychiatric and immune-mediated disorders (e.g., autoimmune,
cardiovascular, metabolic).21,22 The brain not only can affect the immune system, but the
immune system can affect the brain; this bi-directional communication can result in
increased neuroinflammation under chronic stress.23 Increased neuroinflammation while
initially adaptive, if left unchecked can result in aberrant functional and structural changes
in brain regions key to memory and emotional regulation.24,25 For example, acute stress
often enhances memory—a possible survival mechanism to help remember a dangerous
Stress, Sleep, and Inflammation
3
situation—however, chronic stress often impairs memory function.26,27 Prolonged stress can
increase the risk for burnout—a syndrome defined by symptoms of emotional exhaustion
and depersonalization.28,29 If excessive, early life stress may increase the risk for impaired
social skills, aggression, addiction (e.g., food, nicotine, alcohol, drugs), and posttraumatic
stress disorder (PTSD) in adulthood.30-33
Figure 2 | Biological systems involved in the pathophysiology of chronic stress. In the brain,
chronic stress may result in functional changes in brain circuits (for example, in executive,
affective, and salience networks), structural changes in brain volumes (for example, in the
hippocampus), and increased neuroinflammation. Beyond the brain, chronic stress impairs
feedback regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Within the immune system,
there is evidence of increased levels of circulating cytokines and low-grade activation of innate
immune cells, including monocytes. The combination of HPA axis dysregulation and increased
inflammation might converge with other brain and body systems to contribute to psychiatric and
immune-mediated disorders. The sequence of events leading to changes in these interconnected
systems is not known; however, alterations in the stress response system can, directly and
indirectly, affect the brain and other body systems, which suggests a bidirectional link. ACTH,
adrenocorticotropin; CRH, corticotropin-releasing hormone; IL, interleukin; NK, natural killer;
TNF, tumor necrosis factor. Adapted from “Major depressive disorder”, by C. Otte, et al., 2016,
Nature Reviews Disease Primers, 2, p. 8. © 2016 by Macmillan Publishers Limited, part of
Springer Nature. Adapted with permission.
Heather L Rusch
4
1.2 POSTTRAUMATIC STRESS DISORDER
Posttraumatic stress reactions have roots stretching back centuries and were widely known
to previous generations as combat fatigue, shell shock, soldier’s heart, or war neurosis.34
However, it was not until 1980 that PTSD became a household name and was officially
recognized in the third edition of the Diagnostic and Statistical Manual of Mental Disorder
(DSM-III).35 Since then our understanding of PTSD has grown significantly; nonetheless,
the field of traumatic stress is still riddled with controversy over the actual diagnostic
features of PTSD, its causation, and what constitutes evidence-based treatment.36-38
1.2.1 Diagnostic features
Currently, there are two recognized definitions of PTSD—the Diagnostic and Statistical
Manual of Mental Disorders, Fifth Edition (DSM-5), published in 2013 by the American
Psychiatric Association, and the International Classification of Diseases, 11th Revision
(ICD-11), released in 2018 by the World Health Organization (Table 1). Both PTSD
definitions require that the individual witnesses or experiences firsthand an extremely
traumatic event (e.g., actual/threatened death, severe injury, or sexual violence). If that
criterion is met, the DSM-5 requires the manifestation of at least one of five intrusion
symptoms, one of two avoidance symptoms, two of seven alterations in cognitions and
mood, and two of six alterations in arousal and reactivity.39 Instead, the ICD-11 requires the
manifestation of at least one of two intrusion symptoms, one of two avoidance symptoms,
and one of two alterations in arousal and reactivity.40 These symptoms must persist for at
least one month, cause clinically significant distress or impairment in social, occupational,
or other key areas of functioning, and not be attributed to the effects of a substance (e.g.,
alcohol, medication) or another medical condition (e.g., hypothyroidism, seizure).39
1.2.2 Diagnostic discrepancies
Historically, the DSM and ICD have been concordant with their PTSD definitions.
However, in the latest revisions, the DSM-5 expanded its scope to include three new
symptoms, while the ICD-11, in a strategic effort to improve diagnostic accuracy, narrowed
its focus to the core fear-based symptoms of PTSD.41,42 The effect of these modifications is
clinically significant, as several studies report that more individuals are diagnosed with
PTSD using the DSM-5 criteria compared with the ICD-11 criteria.43,44 Moreover, both
definitions identify different individuals as having PTSD.45 Another concern surrounds the
inherent virtues of the two diagnostic definitions. On one side, the DSM-5 criteria apply to
a larger population of trauma-exposed individuals with more diverse symptoms; however,
Stress, Sleep, and Inflammation
5
the inclusion of broader symptoms may increase the rate of misdiagnosing other mental
health conditions as PTSD.45-50 This has serious implications for making treatment
recommendations and for the discovery of meaningful biomarkers.51
Table 1 | Comparison of the DSM-IV, DSM-5, and ICD-11 symptom criteria for PTSD.
Clusters
Symptoms
DSM-
IV
DSM-
5
ICD-
11
INTRUSION
1. Repeated, disturbing, and unwanted memories of the
stressful experience
Ö
Ö
2. Repeated, disturbing dreams of the stressful experience
Ö
Ö
Ö
3. Suddenly feeling or acting as if the stressful experience
were happening again
Ö
Ö
Ö
4. Feeling very upset when something reminded you of the
stressful experience
Ö
Ö
5. Having strong physical reactions when something
reminded you of the stressful experience
Ö
Ö
AVOIDANCE
1. Avoiding memories, thoughts, or feelings related to the
stressful experience
Ö
Ö
Ö
2. Avoiding external reminders of the stressful experience
Ö
Ö
Ö
ALTERATIONS
IN MOOD AND
COGNITION
1. Trouble remembering important parts of the stressful
experience
Ö
Ö
2. Having strong negative beliefs about yourself, other
people, or the world
Ö
3. Blaming yourself or someone else for the stressful
experience or what happened after it
Ö
4. Having strong negative feelings such as fear, horror,
anger, guilt, or shame
Ö
5. Loss of interest in activities you used to enjoy
Ö
Ö
6. Feeling distant or cut-off from other people
Ö
Ö
7. Trouble experiencing positive feelings
Ö
Ö
ALTERATIONS
IN AROUSAL
AND
REACTIVITY
1. Irritable behavior, angry outbursts, or acting
aggressively
Ö
Ö
2. Taking too many risks or doing things that could cause
you harm
Ö
Ö
3. Being “super alert” or watchful or on-guard
Ö
Ö
Ö
4. Feeling jumpy or easily startled
Ö
Ö
Ö
5. Having difficulty concentrating
Ö
Ö
6. Trouble falling or staying asleep
Ö
Ö
Symptoms are reproduced from the PTSD Checklist for DSM-5, a 20-item self-report measure
that assesses the presence and severity of PTSD symptoms. The ‘Avoidance’ and ‘Alterations in
Mood and Cognition’ symptom clusters are combined into one Avoidance/Numbing symptom
cluster for the DSM-IV. DSM, Diagnostic and Statistical Manual of Mental Disorders; ICD,
International Classification of Diseases; PTSD, posttraumatic stress disorder
1.2.3 Prevalence
The 2014 World Mental Health Survey reported 12-month PTSD prevalence rates at 1.1%
across all respondents (N = 51,295), and at 4.0% in respondents with trauma exposure (N =
47,466).52,53 PTSD prevalence rates are significantly higher in high-income countries
(compared to low), as well as in respondents exposed to sexual assault, physical assault,
Heather L Rusch
6
and organized violence (compared to other trauma types).52,54 The 2014 National Health
Study for a New Generation of U.S. Veterans (N = 20,563) reported PTSD prevalence rates
at 13.5% across all military populations, at 15.7% in deployed veterans, and at 10.9% in
nondeployed veterans.55 Prevalence estimates were higher in deployed men than deployed
women (16.0% vs. 12.5%) but lower in nondeployed men than nondeployed women
(10.5% vs. 12.3%).55 Other studies found sex differences across trauma type (Figure 3). For
example, in the United States, the risk of developing PTSD is higher in men than women
after rape (65.0% vs. 45.9%) but lower in men than women after a physical attack (1.8% vs.
21.3%).56 These disparities may reflect sex and societal role differences that play into the
development, expression, and progression of posttraumatic stress symptoms.57
Figure 3 | Sex differences in trauma exposure and posttraumatic stress disorder (PTSD) in
the United States. (A) Lifetime prevalence of trauma exposure stratified by sex. (B) The
proportion of women and men with a specific trauma exposure who met criteria for PTSD.56
14.5 13.8
6.8 6.9
12.3
3.4
0
9.2
35.6
25
19
11.1
2.8 2.1
6.4
0.7
0
5
10
15
20
25
30
35
40
Witness Accident Threat w/
Weapon
Physical
Attack
Molestation Neglect Combat Rape
Percent
Women Men
A. Lifetime prevalance of experiencing a specific traumatic event, stratified by sex
7.5 8.8
32.6
21.3 26.5
19.7
0
45.9
6.4 6.3 1.9 1.8
12.2
23.9
38.8
65
0
10
20
30
40
50
60
70
Witness Accident Threat w/
Weapon
Physical
Attack
Molestation Neglect Combat Rape
Percent
Women Men
B. Probability of a specific traumatic event being associated with PTSD, stratifed by sex
Stress, Sleep, and Inflammation
7
1.2.4 Comorbidities
Individuals who meet the criteria for one health condition more often meet the criteria for
other health conditions—a phenomenon known as comorbidity. The National Comorbidity
Survey (N = 5,877) found that over 88% of men and 79% of women with PTSD were
diagnosed with at least one other mental health condition.56 The most common concurrent
mental health diagnoses were major depression (37.2%), panic disorder (33.3%), social
phobia (19.9%), and substance dependence (10.2%).58 Compared to individuals without
PTSD, people with PTSD were at increased risk for autoimmune, cardiovascular, digestive,
metabolic, musculoskeletal, and neurodegenerative disorders, as well as life-threatening
infections.59-62 The elevated occurrence of comorbid conditions seen in PTSD is likely
mediated by a combination of genetic and environmental factors; however, the precise
contribution of these mediators is still widely unknown. There is also a substantial
symptom overlap between PTSD and comorbid conditions—especially mild traumatic brain
injury (mTBI) in military populations—so the high rate of comorbidity could partly result
from an epiphenomenon of the diagnostic criteria.63
1.3 SLEEP
Sleep is an essential human behavior that is characterized by a reversible state of
diminished receptiveness and loss of consciousness, which is typically initiated in a
recumbent position with eyes closed.64 Recent advances in sleep research indicate that sleep
may play a critical role in emotional regulation, cognitive function (including memory
processing and consolidation), immune regulation, and brain waste removal.65,66 Adequate
and quality sleep supports the functioning of almost every type of tissue and system in the
body. Meta-analyses (Ns > 2,000,000) found that insufficient sleep (less than 7 hours) and
prolonged sleep (more than 9 hours) were associated with increased risk for all-cause
morbidity and cardiovascular events.67,68 Sleep is regulated by a two-process system
comprised of sleep-wake homeostasis and circadian rhythms.69 Sleep-wake homeostasis
means that sleep intensity and duration increases after a prolonged period without sleep.70
In other words, the greater the sleep deficit, the greater the need to fall asleep and stay
asleep longer. Circadian rhythms, on the other hand, modulate the timing of sleep. The
central circadian clock is located in the suprachiasmatic nucleus, a small region of the brain
in the hypothalamus. This system is responsible for imposing and synchronizing a close to
24-hour rhythm on multiple bodily systems, including the proclivity to be awake or asleep
at a particular time.70
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1.3.1 Stages of sleep
Sleep is divided into distinct stages marked by a discrete pattern of brain activity that can
be measured by electroencephalography during polysomnography (i.e., sleep study). Rapid
eye movement (REM) sleep and non-rapid eye movement (NREM) sleep are the two main
stages of sleep. In humans, NREM sleep is further divided into three stages, N1, N2, and
N3 (formerly stages 3 and 4), which correspond to a range of sleep depths.71 Stage N1
marks the transition between wakefulness and sleep, which is typically followed by stage
N2—collectively, these are lighter stages of sleep.72 Stage N3, also referred to as slow-
wave sleep (SWS) due to the preponderance of high-amplitude, low-frequency waves, is
the deepest of all sleep stages.72 The fourth stage is REM sleep, brain activity during REM
sleep resembles the waking brain and most dreaming occurs during this sleep stage.72 An
average night of sleep contains four to six NREM-to-REM sleep cycles, in which each
cycle lasts about 80 to 110 minutes.72 Stage N3 sleep (i.e., SWS) predominates during the
first half of the night, while REM sleep increases as the night progresses (Figure 4A).72 The
different stages of sleep are defined by specific brain oscillations measured by
polysomnography (Figure 4B). For example, SWS sleep is characterized by slow
oscillations (0.5-4 hertz), slow spindles (9-12 hertz), and fast spindles (12-15 hertz).73
Figure 4 | Sleep architecture and sleep oscillations. (A) Human nocturnal sleep profile. (B)
Theta oscillations are prominent during rapid eye movement (REM) sleep. Neocortical slow
oscillations, thalamocortical spindles, and hippocampal ripples are signatures of non-rapid eye
movement (NREM) sleep. Slow oscillations and spindles are hallmark features of slow-wave
sleep (SWS). Adapted from “Mechanisms of systems memory consolidation during sleep”, by J.
G. Klinzing, et al., 2019, Nature Neuroscience, 22, p. 1603. © 2019 by Springer Nature
America, Inc. Adapted with permission.
Stress, Sleep, and Inflammation
9
1.3.2 Measurements of sleep
Sleep quality is determined by a collection of sleep parameters, most commonly, total sleep
time, sleep onset latency (the time it takes to fall asleep once in bed), wake after sleep onset
(the time spent awake after initially falling asleep), and sleep efficiency (the percentage of
time spent asleep while in bed).74 Sleep quality can be measured objectively (by
instrument) or subjectively (by self-report). The most common objective measures used in
clinical and research settings are the polysomnography and actigraphy. Traditionally, the
laboratory-based polysomnography is considered the gold standard measure of sleep
quality; however, it is impractical for long-term use and home utilization (e.g., resource-
demanding, difficult to use).75 During polysomnography, electrodes and sensors are placed
on the body to monitor brain activity, muscle activity, eye movement, heart rhythm,
respiratory rate, blood pressure, and blood oxygen levels. Actigraphy, on the other hand, is
a watch-like device that measures gross motor activity from which estimates of sleep-wake
patterns are made. Actigraphy has similar validity to polysomnography in assessing sleep
parameters in healthy populations but tends to overestimate sleep quality in sleep disturbed
populations.76 This is partly due to mischaracterizing states of laying still while awake as
states of sleep.76 There are several questionnaires that measure subjective sleep quality
retrospectively (e.g., over the past month) or diaries that measure subjective sleep quality
prospectively (e.g., every night for the next week). The correlation between objective and
subjective measures of sleep quality is low, which suggests that the two methods measure
different dimensions of sleep.77 Still, other theories have suggested that individuals with
insomnia experience ‘sleep state [mis]perception’—a trend to underestimate total sleep
time and overestimate sleep onset latency.78,79 Nonetheless, subjective measures of sleep
quality (compared to objective measures) seem to be better predictors of health outcomes in
at least some clinical populations, including PTSD.80,81
1.3.3 Link between sleep and posttraumatic stress
Sleep disturbances, including difficulties initiating and maintaining sleep, are reported in
over 70% of individuals with PTSD.82 Burgeoning evidence suggests that sleep disturbance
is not merely a symptom of PTSD but instead plays a role in the development and
maintenance of posttraumatic stress symptoms.83 Multiple longitudinal studies have
indicated that pre-trauma or peri-trauma sleep disturbances contribute to the prediction of
new-onset PTSD,84-89 with meta-analytic findings reporting that sleep disturbance yields a
three-fold increased risk for anxiety.90 For example, in a longitudinal study of National
Guard Soldiers (N = 522), predeployment daytime and nighttime sleep complaints
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contributed to the prediction of new-onset PTSD at two years postdeployment.91 While
sleep disturbance is reported to predict future PTSD, baseline posttraumatic stress
symptoms did not predict subsequent sleep disturbance or even subsequent PTSD.92,93
Evidence of polysomnography-measured sleep irregularities in PTSD were also found in
two meta-analyses.94,95 The first study (N = 722) reported increased stage N1 sleep (i.e.,
light sleep) and decreased SWS (i.e., deep sleep) in participants with PTSD compared to
controls.94 The second study (N > 2000) also reported decreased SWS, which was
associated with PTSD symptom severity; however, no difference in stage N1 sleep was
found.95 Accumulating evidence also supports the inhibition and/or disruption of REM
sleep in the acute phase of PTSD, which hints at a possible pathogenic marker of symptom
progression.96-100 Taken together, these findings demonstrate the interplay between sleep
quality and PTSD; however, the extent to which posttraumatic stress symptoms can be
mitigated by targeting sleep disturbance directly is less clear.
1.4 INFLAMMATION
The immune system is the body’s defense system against pathogens. Its main purpose is to
identify and remediate internal and external threats like bacteria, fungi, parasites, viruses,
and injury. Cells of the immune system circulate throughout the body and are roughly
grouped into two systems: the innate immune system and the adaptive immune system. The
innate immune system responds rapidly to threats upon the first encounter. Meanwhile, the
adaptive immune system takes several days to respond but does so in a tailor-specific way
that is sustained by memory cells that prime for threat reencounter.70 When the innate
immune system detects a threat, it initiates a cascade of inflammatory responses to contain
the spread of infection and stimulate healing to damaged tissue.101 The inflammatory
mediators involved in these responses are cytokines, chemokines, prostaglandins, and
vasoactive amines, which incite an array of processes aimed at restoring homeostasis.101
Locally, these processes result in clinical signs of inflammation (i.e., redness, swelling,
warmth, pain, and impaired function), rapid release of antimicrobials, and phagocytosis.70
Systemically, these processes result in symptoms like fever and sickness behavior, which is
characterized by anorexia, adipsia, anxiety, anhedonia, fatigue, pain sensitivity, sleep
alterations, and social withdrawal.70,102 Under healthy conditions, acute inflammation is a
protective mechanism for the body. On the other hand, when chronically sustained,
inflammation can cause serious damage to the organism’s own tissues and organs,
including the brain (Figure 5).103
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Figure 5 | Brain milieu changes in response to chronic systemic inflammation. The main
cells present in the brain are neurons, oligodendrocytes, astrocytes, and microglia. Under healthy
conditions (left), neurons connect to each other through long axonal processes with synapses.
Oligodendrocytes support axons with myelin sheaths. Astrocytes interact with blood vessels to
form the blood-brain barrier and support neuronal synapses. Microglia form long processes that
surveillance the brain and phagocytose apoptotic cells and prune inactive synapses without
induction of inflammation. Under chronic inflammatory conditions (right), several mechanisms
can lead to neurodegeneration. Peripheral immune cells and inflammatory molecules traverse the
blood-brain barrier exerting direct and indirect neuronal cytotoxicity. Oligodendroglial myelin
sheaths can be affected leading to axonal degeneration. An influx in astrocytes can lead to
reduced blood-brain barrier and synaptic maintenance. An influx in microglia can lead to a pro-
inflammatory phenotype with reduced phagocytic and tissue maintenance functions. Adapted
from “Systemic inflammation and the brain: novel roles of genetic, molecular, and
environmental cues as drivers of neurodegeneration”, by R. Sankowski, et al., 2015, Frontiers in
Cellular Neuroscience, 9, p. 4. © 2015 by Frontiers, Inc. Adapted with permission.
1.4.1 Measurements of inflammation
The most common methods to measure inflammation directly are to quantify protein
biomarkers (e.g., C-reactive protein (CRP), proinflammatory cytokines) or the molecular
biomarkers that regulate them (e.g., gene expression). Gene expression is the process by
which information from a gene is used to direct the assembly of a protein (Figure 6). It is
the fundamental process by which the genotype (i.e., genetic characteristic) gives rise to the
phenotype (i.e., physical characteristic). Gene expression levels—the quantity of messenger
RNA (mRNA) transcripts—are not static; these levels can be downregulated or upregulated
dependent on genetic determinants, epigenetic modifications, and environmental factors,
including stress and trauma exposure.104 Gene expression analysis is a laboratory technique
that allows for the unbiased identification of dysregulated gene expression levels across the
whole transcriptome in a target population.105 Dysregulated mRNA transcripts can then be
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aggregated into networks and pathways based on their biological function (e.g., immune
response pathway). However, a prominent problem of using gene expression analysis to
measure inflammation in populations with psychiatric disorders is that individual gene
expression differences are usually modest, which makes it difficult to distinguish true
alterations from normal human variation. Some reasons for this include: mRNA transcripts
can encode for several different proteins and the levels of mRNA transcripts do not always
correspond with the levels of proteins they encode for.106 This makes protein biomarker
analysis an important downstream complement to measure inflammation. While direct
sampling of the brain is not readily assessable in living humans, protein biomarkers
assessed in peripheral blood can provide a surrogate indicator of neuroinflammation in the
brain.107 However, conclusions must be tempered since inflammation assessed in peripheral
blood does not always correlate with cerebral spinal fluid levels,108 and peripheral blood
levels may be subject to a blunted circadian rhythm.109,110 Nonetheless, the emerging role of
biomarkers in psychiatry marks a retreat from a purely symptom-based diagnostic system,
which is vulnerable to interpretation and subjective reporting. Moreover, the identification
of biological systems associated with risk and symptom severity holds promise for the
development of diagnostic tests, prognostic indicators, prophylactics, and treatments for
trauma-exposed populations.111
Transcriptome: all RNA transcripts,
including coding and non-coding
Transcriptomics: the study of the
transcriptome and its function
Transcription: the process by which
information in DNA is copied into
an mRNA transcript
Translation: the process by which
protein is synthesized from
information contained in an mRNA
transcript
Gene expression analysis: the
quantification of mRNA transcripts
Figure 6 | An overview of the flow of information from gene to protein in a human cell.
First, both protein-coding and noncoding regions of DNA are transcribed into RNA. Some
regions are removed (e.g., introns) during initial RNA processing. The remaining exons are then
spliced together, and the spliced messenger RNA (mRNA) molecule (red) is prepared for export
out of the nucleus through the addition of an endcap (sphere) and a polyA tail. Once in the
cytoplasm, the mRNA can be used to construct a protein. Adapted from “Essentials of Cell
Biology”, by C.M. O’Connor & J. U. Adams, 2010, NPG Education, Cambridge, MA. © 2010
by Nature Education. Adapted with permission.
Stress, Sleep, and Inflammation
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1.4.2 Link between inflammation and posttraumatic stress
When stress is chronic, the immune system can become dysregulated, and proinflammatory
cytokines [e.g., interleukin-1beta (IL-1β), interleukin-6 (IL-6), interferon-gamma (IFNγ),
and tumor necrosis factor-alpha (TNF-α)] can increase in the periphery. These peripheral
inflammatory mediators can communicate with the brain.23 Additionally, chronic stress can
activate microglia (resident cells within the brain) and cause the release of inflammatory
mediators, including proinflammatory cytokines, within the brain.112 Taken together, the
consequences of these two processes may increase neuroinflammation and putatively
contribute to the onset or severity of psychiatric symptoms.113,114 A 2015 meta-analysis (N
= 1348), indicated that individuals with PTSD had increased blood levels of IL-1β, IL-6,
and IFNγ compared with controls.115 Of note, these meta-analytic findings remained
significant even after excluding studies that included participants with comorbid major
depressive disorder from the analysis.115 Moreover, when studies with medication naive
participants were exclusively analyzed, these same protein biomarkers plus levels of TNF-α
were higher in individuals with PTSD compared to controls.115 This is particularly
important given that major depressive disorder and medication use commonly occur with
PTSD and are also associated with changes in levels of inflammation.116 A second 2018
meta-analysis (N = 1077), which solely included studies with clinician diagnosed
participants, reported that individuals with anxiety disorders, obsessive-compulsive
disorder, and PTSD had elevated blood levels of IL-1β, IL-6, and TNF-α compared to
healthy controls.117 Despite these findings, the observational design of the included studies
restricted the meta-analyses from determining causal associations.118 Several studies also
suggest molecular biomarkers that regulate the proinflammatory milieu in PTSD. For
example, a mega-analysis of blood transcriptome studies (N = 511) found that the innate
immune, cytokine, and type I interferon signaling pathways were associated with PTSD
across all three case-control groups: men exposed to combat traumas, men exposed to
interpersonal traumas, and women exposed to interpersonal traumas.119 Nevertheless,
further work is needed to determine the extent to which these biomarkers can serve as
specific and sensitive markers of posttraumatic stress symptoms.
1.4.3 Link between inflammation and sleep
The existence of a bidirectional relationship between sleep and the immune system is well-
recognized—sleep helps regulate important immune functions, and the immune system
regulates certain aspects of sleep.120 Although sleep plays an essential role in regulating the
innate immune system, the evidence linking sleep to systemic inflammation is inconsistent.
Heather L Rusch
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This variability could be partly explained by the diverse parameters used in clinical trials to
assess sleep quality (e.g., objectively measured, clinician assessed, or self-reported), as well
as the duration of sleep deprivation (e.g., years, days, one night, or part of a night). In this
respect, a recent meta-analysis (N > 50,000) of blood-based biomarkers found that
subjectively measured sleep duration (i.e., clinician assessed or self-reported) was not
associated with levels of CRP (n = 3490) or IL-6 (n = 2084).121 There was also no
association between objectively measured sleep duration and levels of CRP (n = 1550);
however, objectively measured short sleep durations were correlated with higher levels of
IL-6 (n = 489).121 In studies that used a combination of objective and subjective measures,
short sleep durations were correlated with higher levels of CRP (n = 5040) but were not
associated with levels of IL-6 (n = 2573) or TNF-α (n = 157).121 A meta-analysis of
experimental sleep deprivation studies found no evidence of altered levels of CRP (n =
218), IL-6 (n = 263), or TNF-α (n = 109) following sleep restriction over 2 to 12
consecutive days, for one night, or for part of a night—sleep was reduced from 8 hours to 4
hours.121 Adding to these inconsistencies, partial sleep deprivation was shown to upregulate
transcription of IL-6 and TNF-α mRNAs, while improved sleep quality following
standardized sleep treatment was found to downregulate transcription of inflammatory-
related mRNAs.122-124 This highlights the variations of findings and the importance of
utilizing a combination of objective and subjective sleep measures and analyzing both
protein and molecular biomarkers to capture a more comprehensive picture of the
relationship between sleep disturbance and inflammation.
1.5 THESIS RATIONALE
In 2017 the American Psychological Association published their most recent clinical
practice guidelines for the treatment of adults with PTSD.125 Based on the strength of
scientific evidence and patient preference, the guidelines recommended trauma-focused
psychotherapy over pharmacotherapy as a first-line treatment for PTSD.125 At the heart of
trauma-focused psychotherapy is imaginal and in vivo exposure to trauma reminders. This
therapy is based on the premise that PTSD emerges due to the development of a fear-based
memory.126 In theory, effective therapy involves correcting the pathological elements of the
fear-based memory by first reactivating the memory so it is labile and then introducing new
information that corrects the existing pathological components.127 While trauma-focused
psychotherapies are efficacious for some patients, these treatments tend to be less effective
in military populations.128 For example, between 30 to 51% of military service members do
not demonstrate clinically meaningful symptom reduction, and remission rates are as low as
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15
17 to 27%.129 Even when trauma-focused psychotherapy is combined with medication, no
additional improvements are found.130,131 Thus, there is a need for improving existing
PTSD treatments in military populations, with a better understanding of patient preference,
disease mechanisms, and biomarkers underlying treatment response. This next section will
briefly review the inextricable link between stress, sleep, and inflammation and alternative
interventions that target these systems will be discussed.
1.5.1 Link between stress, sleep, and inflammation
Most people experience some type of adversity or trauma in their lifetime. The body is
designed to activate the stress response system at low levels in response to these types of
events.132 However, when there is sustained engagement of the stress response system, due
to persistent psychosocial stress, or ruminating over past or future stressors, levels of
inflammation can increase in the periphery and in the brain (Figure 7).133,134 Theoretically,
this increased inflammation, may induce a biphasic shift in sleep patterns—initially, sleep
continuity is increased in an effort to restore homeostasis (not illustrated); then later, sleep
continuity is decreased paired with an increase in sleep architecture disturbances.135,136 Due
to the bi-directional relationship between sleep and the immune system, prolonged sleep
disturbance may shift molecular and protein profiles to those with increased inflammatory
expression.136 Figure 7 illustrates how this chronic inflammatory state might contribute to
the maintenance of PTSD (including its resistance to treatments) and explain its high
comorbidity with other mental and physical health conditions.137 Furthermore, PTSD
triggers may create a vicious feedback cycle and compound symptoms. Therefore,
interventions that target the reciprocal sleep–immune relationship may have the potential to
redirect this askew inflammatory expression and reduce stress-related symptoms.
Figure 7 | Proposed model of how psychosocial stress may contribute to disease states. CRP,
C-reactive protein; IL, interleukin; NF-κB, nuclear factor-kappa B; PTSD, posttraumatic stress
disorder; REM, rapid eye movement; SWS, slow-wave sleep; TNF, tumor necrosis factor.
Brain
Psychosocial Stress
•Life adversity
•Trauma-exposure
Chronic Inflammation
•↑ Molecular inflammation
(NF-κB)
•↑ Systemic inflammation
(CRP, IL-6, and TNF)
•↑ Cellular inflammation
(monocyte activation)
Inflammation
↑
Disturbance of
sleep continuity
↓ Total sleep time
↓ Sleep efficiency
Disturbance of
sleep architecture
↑ REM sleep
↓ SWS
Disease States
•Cancer
•Cardiac arrest
•Diabetes
•PTSD
•Anxiety
•Depression
•Dementia
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1.5.2 Sleep-focused treatments
As new evidence points to sleep disturbance as a predictor of PTSD onset and relapse,
sleep-focused treatments may be an effective and systemic means to mitigate posttraumatic
stress symptoms, as well as the putative underlying inflammation. Sleep-focused treatments
may also be preferred to trauma-focused psychotherapies due to the stigma associated with
mental health issues, especially by military personnel.138 Cognitive behavioral therapy for
insomnia (CBT-I) is a first-line treatment for insomnia, which targets maladaptive sleep-
related thought patterns and behaviors.139 A 2015 meta-analysis (N = 2189) reported that
36% of insomnia participants who received CBT-I were in remission from insomnia and the
CBT-I had similar positive effects on co-occurring mental and physical health symptoms.140
Although these results are promising, a sizable percentage of the population still remained
symptomatic. This highlights the need to investigate the efficacy of alternative
interventions that target stress, sleep, and inflammation, directly or indirectly.
1.5.3 Mindfulness meditation programs
Mindfulness is a type of meditation with roots in an ancient Buddhist practice called
Vipassanā.141 In a research context, mindfulness is typically defined as paying attention in a
particular way: on purpose, in the present moment, and non-judgmentally.142 In recent
years, mindfulness meditation has gained interest as a transdiagnostic intervention linked to
improvements in various mental and physical health outcomes.143 In clinical trials,
mindfulness-based stress reduction (MBSR) is the most popular mindfulness-based
intervention tested; it includes eight weekly, 2.5-hour in-class sessions with daily
homework exercises. Modified courses have since been created, such as mindfulness-based
cognitive therapy (MBCT), a hybrid of MBSR and CBT. Mindfulness meditation is
hypothesized to target brain regions implicated in cognition and emotional regulation.144 It
has been shown to decrease emotional reactivity, diminish ruminative thoughts, and
facilitate the impartial reappraisal of salient events.145-148 Systematic reviews have reported
tentative evidence that mindfulness meditation reduces physiological markers of stress,
blood levels of CRP, and expression levels of NF-κB.149,150 Several meta-analyses have
investigated the effect of mindfulness meditation on sleep quality; however, the results have
been inconclusive.151-153 Of these, the most robust meta-analysis reported insufficient
evidence to draw any conclusions due to the limited number of available trials (n = 8) at the
time of publication in 2014.153 Since then, there has been an exponential growth in
mindfulness research, thus its potential effect on sleep quality warrants another review.
Stress, Sleep, and Inflammation
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1.5.4 Integrative medicine programs
Integrative medicine programs include mindfulness practices, but also make use of other
conventional and alternative evidence-based methods to support the body's innate healing
response using the least invasive methods as appropriate (Figure 8).154 Integrative medicine
is patient-centered care that goes beyond the treatment of the initial symptoms and aims to
address all potential causes and consequences of disease.155 This has important implications
for military service members who often present with chronic conditions, including the
signature polytrauma triad of chronic pain, mTBI, and PTSD.156 Several theoretical models
of integrative medicine have been proposed depicting putative mechanisms of action. The
most commonly-cited include the emphasis on the mindbody connection and the patient-
practitioner alliance and their collaboration in designing and implementing a
comprehensive treatment plan.157 Unlike more robust clinical trials, which attempt to
control for extraneous factors (by randomizing and blinding etc.), integrative medicine
leverages a patient’s preferences, perspectives, and beliefs, as well as the patient-
practitioner relationship to enhance the effect of the intervention.158 As such, the outcome
does not occur in isolation from the extraneous factors, but in synergy with them.
Investigation of the program’s effectiveness typically treats the program as a synergistic
bundle without dissecting the program components.158
Figure 8 | The Wheel of Health - The Osher Center for Integrative Medicine, Vanderbilt
University Medical Center. The Wheel of Health illustrates the integrative approach to healing
and wellness. It is patient-centered and complements traditional care with additional therapies
that are backed by scientific evidence to improve health and promote healing. © 2015 Vanderbilt
University Medical Center. Reprinted with permission.
© 01 VUMC
Heather L Rusch
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Mindfulness
Intervention ↑
Resilience
Factors ↑
Sleep Quality
↑
Stress and
PTSD ↓
Peripheral
Inflammation ↓
Study
I
Study
II
Study
III
Study
IV
Model depicting the inter-relationship of all four studies.
Stress, Sleep, and Inflammation
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2 STUDY AIMS
The general aim of this thesis was to examine the inextricable link between stress, sleep,
and inflammation, and how gaining a better understanding of these interconnected systems
could be harnessed to develop enhanced treatments for populations with stress-related
symptoms and disorders. The aims for each study follow.
STUDY I
investigated the effect of 4 to 8 weeks of CBT-I and automatic positive
airway pressure (APAP) therapy on posttraumatic stress symptoms, as
well as the gene expression pathways that may mediate this effect in
sleep disturbed military service members with and without PTSD. The
secondary aim was to determine the gene expression profiles that were
associated with each of the three PTSD symptom clusters: intrusions,
avoidance/numbing, and arousal symptoms.
STUDY II
was a meta-analysis that assessed the effect of mindfulness meditation
on sleep quality outcomes when compared to specific active controls
(i.e., evidence-based sleep treatments) and nonspecific active controls
(i.e., time/attention matched placebo controls) in sleep disturbed adults
with a mental and physical health condition. The secondary aims were to
assess for a long-term effect at 5- to 12-month follow-up and assess for a
dose-response relationship between in-class meditation hours and sleep
quality improvements.
STUDY III
investigated if sleep quality improvements, following a 4-week
mindfulness-based integrative medicine program, were associated with
reductions in posttraumatic stress (primary outcome), anxiety,
depression, and postconcussion symptoms in sleep disturbed military
service members with mTBI. The secondary aim was to determine if
sleep quality improvements were associated with decreases in plasma
levels of IL-6, IL-10, and TNF-α.
STUDY IV
investigated the effect of a brief 5-week (7.5-hour) mindfulness-based
program on perceived stress symptoms in moderately stressed healthcare
professionals. Secondary outcomes included burnout, anxiety, positive
and negative affect, state and trait mindfulness, and self-care.
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In the great drama of existence,
We are audience and actors at the same time.
― Niels Bohr
Stress, Sleep, and Inflammation
21
3 METHODS
This thesis included a range of methods and a comprehensive account can be found in the
corresponding manuscripts (see Chapter 9. Appendix). Sleep-focused interventions were
complemented with mechanistic studies of molecular and protein biomarkers. Since
participant enrollment for this thesis began in 2013, the DSM-IV definition of PTSD is
consistently used throughout all relevant studies. In Study I and Study III a combination of
polysomnography, clinician assessed, and self-report measures were used to determine
sleep disturbance. In Study II both actigraphy and self-report measures of sleep quality
were used, but due to the insufficient number of studies that reported on actigraphy data (n
= 2), only the self-report measures of sleep quality were included in the meta-analysis. An
overview of the study design, population, intervention, outcomes, and main statistical test
for each study is presented in Table 2.
Table 2 | Overview of study characteristics.
STUDY I
STUDY II
STUDY III
STUDY IV
Study
Design
Case-Control
Meta-Analysis
Observational
Randomized
Clinical Trial
Population
Sleep disturbed
military service
members with or
without PTSD
Sleep disturbed
adults with a mental
and physical health
condition
Sleep disturbed
military service
members with
mTBI
Moderately
stressed healthcare
professionals
Groups
PTSD = 39
No PTSD = 27
Meditation = 917
Control = 865
Intervention = 93
Meditation = 43
Control = 35
Intervention
CBT-I and
APAP
Mindfulness
meditation
Mindfulness-
based integrative
medicine
Brief mindfulness
meditation
Duration
4 to 8 weeks
2 to 16 weeks
4 weeks
5 weeks
Main
Outcome
Posttraumatic
stress
Sleep quality
Posttraumatic
stress
Perceived stress
Biomarkers
Genome-wide
gene expression
Not included
Plasma IL-6, IL-
10, and TNF-α
Not included
Statistical
Test
ANOVA
Hedges’ g
Linear regression
GLMM
ANOVA, analysis of variance; APAP, automatic positive airway pressure; CBT-I, cognitive behavioral
therapy for insomnia; GLMM, generalized linear mixed models; IL, interleukin; PTSD, posttraumatic
stress disorder; mTBI, mild traumatic brain injury; TNF-α, tumor necrosis factor-alpha
Heather L Rusch
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3.1 STUDY I: METHODS
Study Design
This was a case-control study that investigated the effect of 4 to 8 weeks of CBT-I and
APAP therapy on posttraumatic stress symptoms, as well as the gene expression pathways
that may mediate this effect in sleep disturbed military service members with and without
PTSD. At baseline, participants diagnosed with insomnia received 4 to 8 biweekly sessions
of CBT-I, and participants diagnosed with obstructive sleep apnea received APAP therapy.
Baseline (week 1) and follow-up (week 12) visits included a battery of self-report
questionnaires and blood draws.
Participants
Participants were characterized using the PTSD Checklist—Military Version (PCL-M).159
Participants with a baseline PCL-M score ≥ 50 formed the PTSD group (n = 39) and
participants with a baseline PCL-M score ≤ 25 formed the control group (n = 27); these are
the proposed cut-points for military prevalence.160 At follow-up, the PTSD group was
further divided into two groups: PTSD improved (n = 12; PCL-M change score reduction ≤
-5) and PTSD not-improved (n = 11; PCL-M change score ≥ 0).161
Biomarker Acquisition
Blood was collected into PAXgene tubes (PreAnalytiX Inc.; Hombrechtikon, Switzerland)
and stored at −80 °C until RNA extraction using the PAXgene Blood RNA Kit. Samples
were reverse transcribed using the GeneChip 3′ IVT Expression Kit and hybridized to
Affymetrix HG-U133 Plus 2.0 microarrays (Affymetrix Inc.; Santa Clara, CA, USA).
Statistical Analysis
Analysis of variance (ANOVA) was used to compare baseline gene expression data
between groups and paired t-tests were used to compare baseline to follow-up gene
expression changes within groups. PCL-M symptom cluster subgroups were created using
equal 33.33 percentile cut-points, whereby participants who endorsed the highest symptoms
(high 1/3) were compared with participants who endorsed the lowest symptoms (low 1/3).
Data were analyzed at a ± 2.0-fold change magnitude at a false discovery rate ≤ 0.05 using
Partek Genomics Suite 6.6 (Partek Inc.; St. Louis, MO, USA). This criterion was
determined by a power analysis indicating that the given ANOVA at a ± 2.0-fold change
magnitude, would require 35 samples total for a beta of 0.80.162,163 All gene lists were then
uploaded into the Ingenuity Pathway Analysis (QIAGEN; Redwood City, CA, USA).
Stress, Sleep, and Inflammation
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3.2 STUDY II: METHODS
Systematic Search
This was a meta-analysis that assessed the effect of mindfulness meditation on sleep quality
outcomes when compared to specific active controls (i.e., evidence-based sleep treatments)
and nonspecific active controls (i.e., time/attention matched placebo controls) in sleep
disturbed adults with a mental or physical health condition. PubMed, EBSCO, Embase, and
The Cochrane Library databases were searched for articles through May 2018, with no start
date restriction. For search terms, two main subject-heading domains were combined with
the AND operator: one to designate the intervention (meditation, mindfulness, MBSR,
MBCT, or Vipassanā) and the second to designate the outcome (sleep or insomnia).
Inclusion and Exclusion Criteria
Randomized controlled trials were included in the meta-analysis that enrolled populations
of sleep disturbed adults and employed a mindfulness meditation intervention with sleep
quality assessments at baseline and postintervention. Evidence-based sleep treatments were
determined by an American Academy of Sleep Medicine 2006 report and updated with a
2015 meta-analysis reporting medium to large effects of physical activity on subjective
measures of sleep quality.164,165 Validated sleep measures included both objective and
subjective measures. Trials were excluded that compared mindfulness meditation to an
experimental sleep treatment or compared novice meditators to experienced meditators. All
other populations with clinically significant sleep disturbance, excluding children and
adolescents, were eligible (Table 3).
The Strength of the Body of Evidence
To determine the strength of the body of evidence, three investigators graded the strength of
evidence for each outcome using the grading scheme recommended by the Methods Guide
for Conducting Comparative Effectiveness Reviews.166 In assigning evidence grades, four
domains were considered: risk of bias, directness of outcome measures, consistency of
results, and precision of results. Evidence was classified into the following four categories:
(1) high confidence that the estimate of effect lies close to the true effect, and further
studies would not change the conclusion; (2) moderate confidence that the estimate of
effect lies close to the true effect, and findings are likely to be stable, but some doubt
remains; (3) low confidence that the estimate of effect lies close to the true effect, and that
additional evidence is needed; and (4) insufficient or no evidence to estimate an effect.166
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Table 3 | Detailed inclusion and exclusion summary.
Inclusion
Exclusion
POPULATION
Adult populations with clinically
significant sleep disturbance (i.e.,
insomnia diagnosis or met symptom
severity threshold defined by sleep
quality questionnaires)
Children, adolescents, and experienced
meditators
INTERVENTION
In-person, structured mindfulness
meditation (e.g., mindfulness-based
stress reduction)
Mantra-based meditation, movement-
based therapies like tai chi, and
internet administration
COMPARATOR
Specific active controls:
evidence-based sleep treatments
Nonspecific active controls:
time /attention-matched interventions
Waitlist or usual care controls
OUTCOME
Assessment of a baseline and
postintervention validated objective or
subjective measure of sleep quality
No validated measure of sleep quality
or only a baseline measurement
STUDY DESIGN
Randomized controlled trials
Non-randomized controlled trials
OTHER
All languages and dates through May
2018
Abstracts, reviews, and
non-published trials, as well as
duplicate participant samples
Adapted from “The effect of mindfulness meditation on sleep quality: a systematic review and
meta-analysis of randomized controlled trials”, by H. L. Rusch, et al., 2018, Annals of the New
York Academy of Sciences, 1445(1), p. 7. © 2018 by John Wiley & Sons, Inc. Adapted with
permission.
Outcome Measures
Objective measures of sleep quality included actigraphy. Subjective measures with
established validity included the Insomnia Severity Index (ISI), the Medical Outcomes
Study—Sleep Scale (MOS-SS), and the Pittsburgh Sleep Quality Index (PSQI).167-169 Due
to the high overlap in content validity between the three sleep quality scales, they were
pooled in the meta-analysis.
Statistical Analysis
Quantitative data were analyzed with the Cochrane Collaborative Review Manager
Software (RevMan 5.3).170 Since sleep quality measures differed between trials (e.g., ISI,
MOS-SS, and PSQI), the between-group standardized mean difference was used as the
summary effect estimate of sleep quality and was calculated as Hedges’ g. A meta-analysis
was used to estimate the long-term effects of trials with a follow-up assessment between 5
to 12 months from baseline. To test for relative efficacy, all meta-analyses were stratified
by control type (i.e., specific active control or nonspecific active control). Spearman’s
correlation was used to test for a dose-response relationship between in-class meditation
hours and standardized sleep quality change scores.
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3.3 STUDY III: METHODS
Study Design
This was an observational study that investigated if sleep quality improvements, following
a 4-week mindfulness-based integrative medicine program, were associated with reductions
in neurobehavioral symptoms and decreases in levels of inflammatory biomarkers in sleep
disturbed military service members with mTBI. Participants underwent a 4-week intensive
outpatient program that combines conventional rehabilitation therapies with complementary
wellness interventions. The wellness interventions included acupuncture, biofeedback,
creative arts therapy, and mindfulness practices (e.g., breathing, meditation, yoga). All
interventions were administered by credentialed providers. Baseline (week 1) and follow-up
(week 4) visits included a battery of self-report questionnaires and blood draws.
Participants
A total of 98 military service members consented for this study and 93 met eligibility
criteria. Inclusion criteria included active military service members, 18 years of age or
older, who sustained combat- or mission-related mTBI, with sleep disturbance. Exclusion
criteria included a positive urine pregnancy test (for individuals with childbearing potential)
and an inability to consent. The Ohio State University, Traumatic Brain Injury
Identification Method (OSU TBI-ID) was used to diagnose mTBI, and the Pittsburgh Sleep
Quality Index (PSQI) was used to measure baseline and follow-up sleep quality, and screen
for self-reported sleep disturbance over the prior month.167,171 To provide the maximum
sensitivity (0.90) and specificity (0.87), a total PSQI score of six or more indicated a
positive screen for disturbed sleep. Five military service members did not have sleep
disturbance based on a PSQI score of six or more and were considered ineligible.
Outcome Measures
The primary outcome, the PTSD Checklist—Military Version (PCL-M), was used to assess
self-reported posttraumatic stress symptoms.159 Secondary self-report outcomes included
the General Anxiety Disorder 7-Item (GAD-7), to assess anxiety; the Patient Health
Questionnaire 9-Item (PHQ-9), to assess depression; and the Neurobehavioral Symptom
Inventory 22-Item (NSI-22), to assess postconcussion symptoms.172-174
Biomarker Acquisition
Blood samples were collected through routine venipuncture into ethylenediaminetetraacetic
acid tubes then aliquoted on ice into cryovials. The cryovials were stored upright in a
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−80°C freezer until assayed. The Single Molecule Array HD-1 Analyzer (SIMOA;
Quanterix, Billerica, MA) was used to measure plasma levels of inflammatory biomarkers
using manufacturer’s instructions, consumables, and reagents. The SIMOA’s digital
technology increases sensitivity by 1,000-fold on average over conventional
immunoassays.175 Multiplex technology simultaneously quantified IL-6, IL-10, and TNF-α
in one kit. Samples were batched assayed to minimize variability, and standards and
controls were run with each batch to confirm reliability. All samples were analyzed in
duplicate and all values were above the limit of detection. Samples were rerun when
coefficients of variance exceeded 20%. Data were not used if coefficients of variance were
above 20% after rerun, and intra-assay or inter-assay performance was below 20%.
Statistical Analysis
Statistical analyses were performed using the statistical software R (Version 3.3.3 for Mac;
R Core Team, Vienna, Austria) and SPSS (Version 26 for Mac; IBM Corp, Chicago, IL).
Categorical variables were described in frequencies and percentages and compared with
chi-square tests, while continuous variables were described in means and standard
deviations and compared with unpaired or paired t-tests as appropriate. Results were similar
with and without the outliers, so all available data were included. All tests were two-sided
and a p-value less than 0.05 was considered to be statistically significant. Linear regression
models were used to assess the association between change in sleep quality (from baseline
to follow-up) and change in neurobehavioral symptom severity and change in levels of
inflammatory biomarkers over this same 4-week period. For example, the posttraumatic
stress regression model included PSQI_Change as the predictor variable and PCL-
M_Change as the dependent variable, while also adjusting for PSQI at baseline, PCL-M at
baseline, age, body mass index, race, tobacco use, and alcohol use. In a subgroup analysis,
we conducted repeated-measures ANOVAs to investigate group differences between
participants with improved sleep quality and those with declined sleep quality on changes
in dependent variables found to be significantly associated with sleep from the main
analysis. A three-point reduction on the PSQI is considered the minimal clinically
important difference and was used to distinguish participants with improved sleep quality
(PSQI change score ≤ -3) from those with declined sleep quality (PSQI change score ≥
1).176 Lastly, missing data patterns (e.g., participants who missed follow-up assessments
due to lack of time) were examined with sensitivity analyses, based on imputation, for their
impact on model inferences.
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3.4 STUDY IV: METHODS
Study Design
This was a randomized clinical trial that investigated the effect of a brief 5-week (7.5-hour)
mindfulness-based program on perceived stress symptoms in moderately stressed
healthcare professionals. Participants were randomized into the mindfulness-based self-care
(MBSC) group or the life-as-usual control group. The MBSC group attended five 1.5-hour
mindfulness sessions at the National Institutes of Health, Clinical Center during work
hours. Mindfulness exercises included mindful breathing, body scan, mindful walking,
mindful movements, mindful eating, and loving-kindness meditation. Daily at-home
mindfulness practice was strongly encouraged. Baseline (week 1) and postintervention
(week 5) visits included a battery of self-report questionnaires for both groups, as well as a
follow-up (week 13) visit for the MBSC group only to test for a maintenance effect.
Participants
Participation was open to all National Institutes of Health employees, contractors, and
training fellows. Individuals with psychiatric and medical conditions were advised to
consult with their healthcare providers before enrollment. Two participants in each group
declined to participate after randomization, before the start of the study and did not provide
baseline data. Thus, the modified intent-to-treat analyses included 43 meditation
participants and 35 controls (Figure 9).
Outcomes
The primary outcome, the Perceived Stress Scale 10-Item (PSS-10) was used to assess self-
reported stress.177 Secondary self-report outcomes included the Visual Analog Scale—
Anxiety (VAS-A) to assess anxiety, the Maslach Burnout Inventory 2-Item (MBI-2) to
assess burnout, the Positive and Negative Affect Schedule (PANAS) to assess positive and
negative affect, the Mindful Attention Awareness Scale—Trait and State (MAAS-T and
MAAS-S) to assess trait and state mindfulness, and the Mindful Self-Care Scale—General
(MSCS-G) to assess mindfulness self-care practices.178-182
Statistical Analysis
Sample size was determined by calculating the power to detect a mean change score of 1-
point in perceived stress (PSS-10) between the meditation and control groups from baseline
to postintervention.183 Estimates assumed a moderate-to-strong correlation (rho = 0.5) in
the repeated measures, equal group allocation, two-sided alpha of 0.05, beta of 0.90, and an
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attrition rate of 10 to 15%, which yielded 33 participants per group. Generalized linear
mixed modeling for repeated measures compared postintervention and follow-up measures
between and within the meditation and control groups, as applicable. Mixed models are the
recommended statistical method for analyzing data collected at repeated time points.184
This method has the advantage of making use of all available data, accounting for within-
subject correlations between repeated measurements, and implicitly accounting for data
missing at random. Post-hoc pairwise comparisons were adjusted for multiple comparisons
using the Bonferroni method and reported p-values were corrected for multiplicity. Effect
sizes were bias corrected with Cohen’s d and Hedges’ g.
Figure 9 | CONSORT flow diagram. The study flow starting at enrollment and continuing
through randomization, postintervention, and follow-up. MBSC, mindfulness-based self-care; ITT,
intent-to-treat. Adapted from “Effect of a brief mindfulness-based program on stress in health care
professionals at a US biomedical research hospital: A randomized clinical trial”, by R. Ameli, et
al., 2020, JAMA Open Network, 3(8). © 2020 by the American Medical Association. Adapted
with permission.
82 Assessed for
eligibility
37 Assigned to Life as Usual
35 Per randomization
2 Declined participation
45 Assigned to MBSC Intervention
43 Per randomization
2 Declined participation
82 Randomized
0 Lost at postintervention (week 5)
Included in the ITT analysis
43 At postintervention (week 5)
43 At follow-up (week 13)
5 Lost at postintervention (week 5)
3 Lost at follow-up (week 13)
Reasons:
family emergency
illness
shift change
work obligations
Included in the ITT analysis
35 At postintervention (week 5)
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4 RESULTS
Each study included a series of main and sub-analyses. This section briefly describes the
results for each study; a comprehensive account can be found in the corresponding
manuscripts (see Chapter 9. Appendix). An overview of the main findings for each study is
presented in Table 4.
Table 4 | Overview of study results.
STUDY I
Posttraumatic stress symptom reduction, following 4 to 8 weeks of
CBT-I and APAP therapy, was linked to downregulated cell-mediated
immune response genes and immune cell trafficking genes.a
STUDY II
Mindfulness meditation is an effective treatment to improve sleep
quality in adult populations with various mental and physical health
conditions.
STUDY III
Sleep quality improvements, following a 4-week mindfulness-based
integrative medicine program, were linked to reductions in
posttraumatic stress symptoms, but not to decreases in inflammation.
STUDY IV
A brief 5-week (7.5-hour) mindfulness-based program reduced
perceived stress in moderately stressed healthcare professionals.
APAP, automatic positive airway pressure; CBT-I, cognitive behavioral therapy for
insomnia
a
Downregulation is the process by which a cell decreases the quantity of mRNA transcripts associated with a
particular gene. Upregulation is the complementary process. The terms underexpression and overexpression
are used synonymously.
Heather L Rusch
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4.1 STUDY I: RESULTS
Study I investigated the effect of 4 to 8 weeks of CBT-I and APAP therapy on
posttraumatic stress symptoms, as well as the gene expression pathways that may mediate
this effect in sleep disturbed military service members with and without PTSD. The
baseline demographic and clinical characteristics for the PTSD and control groups are
presented in Table 5.
Table 5 | Baseline demographic and clinical characteristics.
PTSD
(n = 39)
Controls
(n= 27)
x² / t
p-value
Age: n (%)
18 – 35 years
36 – 55 years
27 (69.2)
12 (30.8)
14 (51.9)
13 (48.1)
2.048
0.152
Sex: n (%)
Male
Female
37 (94.9)
2 (5.1)
26 (96.3)
1 (3.7)
0.075
>0.999
Race: n (%)
White
Non-white
25 (64.1)
14 (35.9)
20 (74.1)
7 (25.9)
0.731
0.392
Education: n (%)
No college
Some college
16 (42.1)
22 (57.9)
10 (37.0)
17 (63.0)
0.169
0.681
Body mass index: mean (SD)
29.8 (4.4)
29.6 (3.9)
-0.196
0.846
Complex insomnia: n (%)
18 (46.2)
3 (11.1)
9.031
0.003
mTBI diagnosis: n (%)
29 (74.4)
1 (3.7)
32.125
< 0.001
PTSD severity: mean (SD)
61.3 (7.7)
21.7 (2.7)
-25.552
< 0.001
mTBI, mild traumatic brain injury; PTSD, posttraumatic stress disorder
The first gene expression analysis indicated that, at baseline, 89 genes were differentially
expressed between participants with and without PTSD. Most of these genes (94%) were
upregulated in the PTSD group. The next analysis compared the gene expression
differences, also at baseline, between participants who endorsed high vs. low symptom
severity among the three PTSD symptom clusters (see Table 1 for review). The purpose of
this analysis was first to see if certain genes were associated with specific posttraumatic
stress symptoms and secondly to see if a more robust gene expression profile would emerge
for the intrusion symptom cluster (e.g., reexperiencing, nightmares, and flashbacks) since
these are hallmark features of PTSD. As such, the gene expression analysis indicated that
1040 genes were differentially expressed between participants with high vs. low intrusion
symptoms. Most of these genes (98%) were upregulated in the high intrusion symptom
group. There were no differentially expressed genes between participants with high vs. low
avoidance/numbing symptoms or with high vs. low arousal symptoms.
Stress, Sleep, and Inflammation
31
Of the PTSD participants, 22.6% had clinically meaningful improvements (change score
reduction ≤ -10).
b
The final analysis sought to determine which genes were associated with
symptom improvement in this group. Herein, the gene expression analysis indicated that 18
genes were differentially expressed in the PTSD group with improved symptoms from
baseline to follow-up. All 18 genes’ were downregulated at follow-up and ten of these genes
intersected with the PTSD vs. control differentially expressed gene list and the high vs. low
intrusion symptom differentially expressed gene list, but with an inverse’ relationship
(Figure 10).
Figure 10 | PTSD associated differentially expressed genes. (A) Venn diagram of differentially
expressed genes between analyses. The PTSD and high intrusion symptom associated genes were
mostly upregulated (94% and 98%), whereas the PTSD improved associated genes were all
downregulated. (B) Ten overlapping differentially expressed genes between all three analyses with
fold change score depicting the overexpression associated with posttraumatic stress symptoms and
underexpression associated with posttraumatic stress symptom reduction. Adapted from “Gene
expression differences in PTSD are uniquely related to the intrusion symptom cluster: a
transcriptome-wide analysis in military service members”, by Rusch, H. L., et al., 2019, Brain,
Behavior, and Immunity, 80, p. 906. © 2019 by Elsevier Inc. Adapted with Permission.
The differentially expressed gene lists from the three analyses (see Figure 10) were then
uploaded into Ingenuity Pathway Analysis to calculate the top physiological systems and
networks linked with each gene expression comparison. Briefly, immune response and
immune cell trafficking systems were upregulated in the PTSD group and high intrusion
symptom group at baseline, which were downregulated with posttraumatic stress symptom
improvement at follow-up. Downregulated networks of lipid metabolism, nucleic acid
metabolism, and small molecule biochemistry, with an NF-κB hub, were linked to PTSD
symptom improvement following the CBT-I and APAP therapy (Figure 11).
b
All participants with PTSD were included in this analysis, not only the participants with both baseline and
follow-up gene expression data.
Heather L Rusch
32
Figure 11 | Ingenuity pathway analysis. Ten genes (green) related to PTSD symptom
improvement were linked to downregulated networks of lipid metabolism, nucleic acid
metabolism, and small molecule biochemistry, with a nuclear factor kappa-beta (NF-κB) hub
(blue). Reprinted from “Gene expression differences in PTSD are uniquely related to the
intrusion symptom cluster: a transcriptome-wide analysis in military service members”, by
Rusch, H. L., et al., 2019, Brain, Behavior, and Immunity, 80, p. 906. © 2019 by Elsevier Inc.
Reprinted with Permission.
4.2 STUDY II: RESULTS
Study II was a meta-analysis that assessed the effect of mindfulness meditation on sleep
quality. Eighteen trials with 1654 participants met the inclusion criteria and were included
in the meta-analysis. In-class meditation sessions ranged from 1 to 2.5 hours per week for 2
to 16 weeks. Meditation practice was encouraged at home in all 18 trials; however, 12 trials
specified a practice time, which ranged from 15 to 60 minutes daily. Seven trials offered a
full-day silent meditation retreat, and one trial offered an in-class booster session two
months following the completion of the main program.
The evidence suggests that mindfulness meditation is an effective treatment to improve
sleep quality in adult populations with various mental and physical health conditions. Seven
trials compared mindfulness meditation to evidence-based sleep treatments, such as CBT-I
or medication for insomnia.185-191 The results indicated that mindfulness meditation had a
similar effect on sleep quality compared to the evidence-based sleep treatments at
postintervention (ES -0.03 [95% CI -0.49 to 0.43]) and at a 5- to 12-month follow-up (ES -
0.14 [95% CI -0.62 to 0.34]). However, the strength of this evidence was low due to the
Stress, Sleep, and Inflammation
33
high heterogeneity at both timepoints, and further studies are needed to confirm these
results (Figure 12A). Eleven trials, compared mindfulness meditation to time/attention
matched placebo controls.192-202 The results indicated that mindfulness meditation was
superior to the time/attention matched placebo controls at postintervention (ES 0.33 [95%
CI 0.17 to 0.48]) and at a 5- to 12-month follow-up (ES 0.54 [95% CI 0.24 to 0.84]). The
strength of this evidence was moderate, indicating that the findings are likely to be stable,
but some doubt remains (Figure 12B).
Figure 12 | Between-group relative percent difference in change score for (A) evidence-
based sleep treatments and (B) time/attention matched placebo controls. Author, year, and
sleep scale are noted at the bottom of each cluster bar. Follow-up scores are reported for trials
with a follow-up assessment between 5 and 12 months from baseline. Percent change in sleep
score was calculated using the formula: {[(postintervention meancontrol − baseline meancontrol) −
(postintervention meanmeditation − baseline meanmeditation)]/ (baseline meanmeditation) × 100}.
Positive scores are the relative percent change in favor of meditation. For example, a change
score of 20% indicates the meditation group had a 20% higher improvement in sleep quality
score compared to the control group. *The result is statistically significant per manuscript.
[*]Overall group effect is statistically significant. ISI, Insomnia Severity Index; MOS-SS,
Medical Outcomes Study—Sleep Scale; PSQI, Pittsburgh Sleep Quality Index. Adapted from
“The effect of mindfulness meditation on sleep quality: a systematic review and meta-analysis of
randomized controlled trials”, by Rusch, H. L., et al., 2018, Annals of the New York Academy
of Sciences, 1445(1), p. 11. © 2018 John Wiley & Sons, Inc. Adapted with permission.
Heather L Rusch
34
Seventeen trials reported on in-class meditation hours for the total intervention, which
ranged from 3 to 42 hours (15.6 mean, 9.8 SD), including the full-day retreat. There was no
support for a dose-response relationship between in-class meditation hours and
standardized sleep quality change scores. Six trials evaluated a dose-response relationship
between at-home mediation practice and improvements in sleep quality from baseline to
postintervention. Three trials found a significant positive correlation.185,189,202 While another
three trials identified no relationship.187,191,194
4.3 STUDY III: RESULTS
Study III investigated if sleep quality improvements, following a 4-week mindfulness-based
integrative medicine program, were associated with reductions in neurobehavioral
symptoms and decreases in levels of inflammatory biomarkers in sleep disturbed military
service members with mTBI. The demographic and clinical characteristics for the total
sample are presented in Table 6.
Table 6 | Demographic and clinical characteristics of the total sample.
Baseline
(week 1)
Follow-Up
(week 4)
Variables, No. (%)
Male sex
93 (100)
White race
89 (95.7)
Tobacco users
34 (36.6)
Alcohol users
79 (84.9)
PTSD Dx.
44 (47.3)
21 (22.6)
Anxiety Dx.
60 (64.5)
22 (23.7)
Depression Dx.
60 (64.5)
20 (21.5)
Postconcussion syndrome Dx.
81 (87.1)
31 (33.3)
Variables, mean (SD)
Age, years
40.77 (5.35)
Body mass index
28.56 (3.18)
Total treatment, hours
29.24 (8.71)
Creative arts therapy
9.77 (3.77)
Mindfulness practices
6.93 (3.75)
Other integrative practices
12.55 (7.03)
All diagnoses (Dx.) are provisional based on self-report measures.
From baseline to follow-up the sample as a whole had significant reductions in sleep
disturbance (t73 = 6.449; p < 0.001), posttraumatic stress (t76 = 7.598; p < 0.001), anxiety
(t76 = 11.077; p < 0.001), depression (t75 = 9.731; p < 0.001), and postconcussion symptoms
(t76 = 10.684; p < 0.001), as well as decreases in levels of TNF-α (t82 = 3.246; p < 0.002).
No significant change in levels of IL-6 or IL-10 were observed. The next analysis sought to
Stress, Sleep, and Inflammation
35
determine if there was an association between sleep quality improvements and change in
neurobehavioral symptom severity and inflammatory biomarker levels. Herein the data
indicated that improvements in sleep quality were significantly associated with reductions
in posttraumatic stress (β = 1.286; [95% CI 0.689 to 1.883]; p < 0.001), anxiety (β = 0.568;
[95% CI 0.322 to 0.814]; p < 0.001), depression (β = 0.761; [95% CI 0.504 to 1.017]; p <
0.001), and postconcussion symptoms (β = 1.786; [95% CI 1.054 to 2.518]; p < 0.001)
(Figure 13). Improvements in sleep quality were not directly associated with change in any
of the inflammatory biomarker levels over this same 4-week period.
Figure 13 | Associations between sleep quality improvements and change in posttraumatic
stress symptoms. Change scores were calculated by subtracting the baseline (week 1) value from
the follow-up (week 4) value, hence a negative value indicates a reduction in sleep disturbance
and posttraumatic stress symptoms. PCL-M, PTSD Checklist—Military Version; PSQI,
Pittsburgh Sleep Quality Index
Following the 4-week integrative medicine program, 40.9% of participants reported
clinically meaningful sleep quality improvements, 15.1% reported sleep quality declines,
and 23.7% reported no meaningful difference in sleep quality. Of the PTSD participants,
65.8% had clinically meaningful symptom reduction (change score reduction ≤ -10). For
the subgroup analysis, participants with improved sleep quality (n = 38) were compared
with participants with declined sleep quality (n = 14) to examine the putative role of sleep
quality changes on neurobehavioral symptom severity. Herein, there were significantly
larger reductions in posttraumatic stress (f1,44 = 13.621; p = 0.001), anxiety (f1,45 = 5.694; p
= 0.021), depression (f1,44 = 8.605; p = 0.005), and postconcussion symptoms (f1,44 = 6.969;
p = 0.011), in the sleep improved group. (Figure 14).
A
PCL-M Change Score
PSQI Change Score
Heather L Rusch
36
Figure 14 | Change in neurobehavioral symptom severity from baseline to follow-up
according to change in sleep quality. Change scores were calculated by subtracting the baseline
(week 1) value from the follow-up (week 4) value, hence a negative value indicates a reduction
in neurobehavioral symptoms. GAD-7, General Anxiety Disorder 7-Item; NSI-22,
Neurobehavioral Symptom Inventory 22-Item; PCL-M, PTSD Checklist—Military Version;
PHQ-9, Patient Health Questionnaire 9-Item. Data are depicted as mean change score and
standardized mean error.
4.4 STUDY IV: RESULTS
Study IV investigated the effect of a brief 5-week (7.5-hour) mindfulness-based program on
perceived stress symptoms in moderately stressed healthcare professionals. The baseline
demographic and clinical characteristics for the meditation and control groups are presented
in Table 7. The meditation group had a mean age in years (SD) of 35.7 (15.4) and the
controls had a mean age in years (SD) of 36.4 (13.0).
Table 7 | Baseline demographic and clinical characteristics.
Variable, No. (%)
Meditation
(n = 43)
Control
(n = 35)
Female sex
37 (86.1)
28 (80.0)
Hispanic/Latinx
5 (11.9)
5 (14.3)
Race
American Indian/Alaska Native
Asian
Black
White
Mixed/Other
1 (2.3)
7 (16.3)
3 (7.0)
27 (62.8)
5 (11.6)
0 (0.0)
6 (17.1)
2 (5.7)
21 (60.0)
6 (17.1)
Marital status
Single
Married
Divorced/Separated
Widowed/Other
28 (65.1)
8 (18.6)
3 (7.0)
4 (9.3)
19 (54.3)
12 (34.3)
3 (8.6)
1 (2.9)
Medical condition
16 (37.2)
9 (25.7)
Psychiatric condition
16 (38.1)
14 (40.0)
-13.30
-6.55 -6.73
-20.03
-0.14 -2.93 -2.50
-10.00
-25
-20
-15
-10
-5
0
PCL-M
GAD-7
PHQ-9
NSI-22
Mean Change Score
Improved Sleep (n = 38) Declined Sleep (n = 14)
p= 0.016
p< 0.001
p= 0.011
p= 0.032
Stress, Sleep, and Inflammation
37
To test the effect of the brief 5-week (7.5-hour) mindfulness-based program, the meditation
group was compared with the control group on their change in symptoms and behaviors
from baseline (week 1) to postintervention (week 5). Herein, the meditation group had
significantly larger reductions in perceived stress (∆ -2.50 [95% CI -4.28 to -0.72] vs. ∆ -
0.04 [95% CI -0.37 to 0.29]; p = 0.016) and anxiety (∆ -2.13 [-2.79 to -1.48] vs. ∆ -0.19 [-
0.53 to 0.14]; p < 0.001], as well as significantly larger increases in positive affect (∆ 2.94
[0.70 to 5.18] vs. ∆ -0.33 [-0.68 to 0.02]; p < 0.001], state mindfulness (∆ 1.59 [1.17 to
2.01] vs. ∆ 0.26 [-0.08 to 0.60]; p < 0.001), and mindfulness self-care practices (∆ 1.61
[0.68 to 2.53] vs. ∆ -0.16 [-0.49 to 0.17]; p < 0.001) (Figure 15). There were no significant
between-group differences in burnout, negative affect, or trait mindfulness.
Figure 15 | Between and within-group Perceive Stress Scale-10 (PSS-10) score differences.
The mindfulness-based self-care (MBSC) group had significantly larger reductions in perceived
stress compared with the control group at postintervention (week 5) and these reductions were
maintained through the follow-up assessment (week 13). Data are depicted as mean score and
standardized mean error.
The second analysis sought to determine if the meditation group maintained any potential
benefits gained from the mindfulness-based program two months later. As such, from
baseline (week 1) to follow-up (week 13), the meditation group had additional significant
reductions in perceived stress (∆ = -6.14 [95% CI -7.84 to -4.44]; p < 0.001), maintained
reductions in anxiety (∆ = -1.46 [-1.97 to -0.94]; p < 0.001), and had additional significant
increases in state mindfulness (∆ = 1.89 [1.39 to 2.39]; p < 0.001) (Figure 15). The
increases in positive affect and mindfulness self-care practices observed from baseline to
postintervention were not maintained at follow-up.
18.80 18.54
19.63
17.29
13.80
0
5
10
15
20
25
Week 1 Week 5 Week 13
Mean PSS-10 Score
Controls (n = 35) MBSC (n = 43)
p< 0.001
p= 0.009
p= 0.016
Heather L Rusch
38
When you change the way you look at things,
The things you look at change.
― Max Planck
Stress, Sleep, and Inflammation
39
5 DISCUSSION
The general aim of this thesis was to examine the inextricable link between stress, sleep,
and inflammation, and how gaining a better understanding of these interconnected systems
could be harnessed to develop enhanced treatments for populations with stress-related
symptoms and disorders. The main findings, methodological considerations, clinical
implications, and directions for future research are discussed.
5.1 STUDY I: DISCUSSION
Study I investigated the effect of 4 to 8 weeks of CBT-I and APAP therapy on
posttraumatic stress symptoms, as well as the gene expression pathways that may mediate
this effect in sleep disturbed military service members with and without PTSD. Results
indicated that 22.6% of participants with PTSD had clinically meaningful posttraumatic
stress symptom reduction following treatment (i.e., response rate). The average response
rate for trauma-focused psychotherapy is between 49 to 70% in military populations.129 The
lower response rate in our study seemed to be due to the high noncompliance rate to the
APAP therapy. Typically, noncompliance rates of 20% or more pose serious threats to
treatment efficacy—our noncompliance rate of 66.7% was three times greater than the
accepted standard.203 Even though positive airway pressure therapies, including APAP
therapy, are the most effective treatment for obstructive sleep apnea, compliance is
challenging in populations with PTSD, and approaches to increase adherence are needed.204
In the pathway analysis, genes associated with immune response systems were the most
reliably upregulated pathways that distinguished participants with PTSD from those
without PTSD. These results are supported by our prior transcriptome work (Paper 3) and
the results from a mega-analysis of blood transcriptome studies (N = 511).119,205 Moreover,
the current study extends these findings by showing that posttraumatic stress symptom
reduction, following standardized sleep therapy, is associated with a downregulation of
these same immune response systems. Despite this relationship, the direction of causality
cannot be determined. It is also quite possible that sleep quality improvements reduced both
the severity of posttraumatic stress symptoms and levels of inflammation simultaneously
and independently. Within the same cohort (but not grouping by PTSD) we previously
reported that participants with improved sleep quality, following standardized sleep
therapy, had reduced expression of genes related to inflammatory cytokines with a trend
reduction in posttraumatic stress symptoms (∆ = -3.1 [SD 1.2]; p < 0.067) (Paper 2).124
Heather L Rusch
40
In Study I, we also found that gene expression differences between participants with and
without PTSD were almost exclusively attributed to the intrusion symptom cluster (98%),
and there were no gene expression differences associated with the remaining two symptom
clusters. One justification for these findings is that intrusion symptoms (e.g., nightmares,
flashbacks, and reexperiencing symptoms) are specific to PTSD, whereas pathological
symptoms of avoidance/numbing and arousal overlap with other mental and physical health
conditions common in military populations, most notably depression and mTBI (Figure
16). If participants endorse PTSD-like symptoms that are due to co-occurring conditions—
for example, cognitive deficits incurred from mTBI—the same phenotypic expression
might be represented by different underlying gene expressions and therefore mask between-
group differences. An alternative explanation could be that trauma exposure elicits gene
expression alterations involved in intrusion symptoms, and secondary symptoms of
avoidance, depression, hyperarousal, etc. develop in response. For example, flashbacks
could cause an individual to avoid certain people and places in an effort to minimize
trauma-related triggers and increase a sense of safety. It is also likely that the PTSD group
in our study was comprised of false-positive cases—participants who met the PCL-M ≥ 50
cutoff score by endorsing PTSD-like symptoms due to comorbid conditions. When these
potentially false-positive cases were removed from the analysis, a more robust gene
expression profile emerged.
Figure 16 | Venn diagram of symptom overlap between posttraumatic stress disorder
(PTSD) and mild traumatic brain injury (mTBI). Intrusion symptoms (e.g., reexperiencing,
nightmares, and flashbacks) are specific to PTSD. Whereas avoidance/numbing symptoms (e.g.,
avoidance of people, places, and things that are trauma reminders and cognitive and mood
alterations) and arousal symptoms (e.g., insomnia, irritability, and increased startle) overlap with
other neurobehavioral conditions. Reprinted from “Gene expression differences in PTSD are
uniquely related to the intrusion symptom cluster: a transcriptome-wide analysis in military
service members”, by Rusch, H. L., et al., 2019, Brain, Behavior, and Immunity, 80, p. 906. ©
2019 by Elsevier Inc. Reprinted with Permission.
Stress, Sleep, and Inflammation
41
5.2 STUDY II: DISCUSSION
In order to investigate alternative interventions that may improve sleep quality and
potentially provide additional benefits for stress-related disorders, Study II conducted a
meta-analysis to determine the effect of mindfulness meditation on sleep quality outcomes
in sleep disturbed adults with various mental and physical health conditions. The results
indicated that mindfulness meditation had a similar effect on sleep quality compared to the
evidence-based sleep treatments and was superior to the time/attention matched placebo
controls. The results also suggested that the benefits of mindfulness meditation were
maintained for up to 5 to 12 months following the completion of the study. Mindfulness
research is still in its infancy; however, these long-term effects may have been supported by
sleep architecture changes, functional and structural brain alterations, or increased mastery
of techniques that minimize sleep-disruptive emotional and cognitive processes.206-209
Nevertheless, due to the high heterogeneity and modest number of studies that met our
inclusion criteria, we had low to moderate confidence in these results, and further research
is warranted to confirm our positive findings.
We also found no evidence to support a dose-response relationship between in-class
meditation hours and change in sleep quality. These results are echoed in a meta-analysis
that evaluated the relationship between in-class meditation hours and change in
psychological distress.210 Dose-response relationships are arguably one of the most difficult
metrics in meditation research due to a number of factors. First, it is challenging to
accurately assess how mindful (verse mind wandering) a participant is during meditation
practice.211 Moreover, mediation progress has a multiphasic trajectory, which is often
misunderstood in Western contexts.212 Traditionally, success in meditation is defined by
increased awareness (sati) and equanimity (upekkhā), whereby positive mental and physical
states are a byproduct. When symptom change over a brief period is the only benchmark of
success, meditation progress and its potential effect on wellbeing may be veiled.
5.3 STUDY III: DISCUSSION
Once mindfulness meditation was established as a potential intervention to improve sleep
quality, Study III investigated if sleep quality improvements, following a 4-week
mindfulness-based integrative medicine program, were associated with reductions in
posttraumatic stress, anxiety, depression, and postconcussion symptoms, as well as
decreases in inflammation in sleep disturbed military service members with mTBI. Results
indicated that 40.9% of participants reported clinically meaningful sleep quality
Heather L Rusch
42
improvements, following the intervention, which were linked to reductions in posttraumatic
stress and other neurobehavioral symptoms. These findings were also reflected in the
subgroup analysis where we compared participants with improved sleep quality to
participants with declined sleep quality on the same outcomes. At follow-up, 65.8% of
participants with PTSD and 55% of the entire cohort had clinically meaningful reductions
in posttraumatic stress symptoms. However, the response rates were quite diverse between
the improved sleep group (60%) and the declined sleep group (14%). These findings
suggest that improved sleep quality is involved in posttraumatic stress symptom reduction
and extends this line of inquiry to include other neurobehavioral symptoms. Nonetheless,
the study design tempers any conclusions regarding the direction of causality, and symptom
reduction overall may be due to placebo effects or other factors.
Next, we found a small, but significant decrease in levels of TNF-α over time; however,
these reductions were not associated with improvements in sleep quality. Even though sleep
plays an essential role in regulating the innate immune system, evidence of this direct
relationship may not have been captured by our choice of sleep quality assessment (the
PSQI self-report measure) or duration of study assessment (4-week period). In this respect,
a comprehensive meta-analysis (N > 50,000), found that levels of inflammatory biomarkers
such as CRP, IL-6, and TNF-α were subject to the diverse parameters used in clinical trials
to assess sleep quality (e.g., objectively measured, clinician assessed, or self-reported), as
well as the duration of sleep deprivation (e.g., years, days, one night, or part of a night).121
It is also possible that the decreased levels of TNF-α may have been a downstream effect in
response to a reduction in neurobehavioral symptoms and not in response to sleep quality
improvements.118,213 Lastly, we cannot rule out that such observation was not due to diurnal
variation or natural variation over time.214,215 We also did not observe significant changes in
levels of IL-6 and IL-10 over time or in association with improvements in sleep quality.
Sex differences are one possible reason for these findings.216 The current cohort was
comprised solely of men and prior studies investigating human adult molecular and protein
biomarkers have more often indicated stronger links between sleep disturbance and
inflammation in women than in men.217,218 This sexual dimorphism is thought to be driven
at least in part by the differences in reproductive hormones between the two sexes.218,219
5.4 STUDY IV: DISCUSSION
We found some evidence that posttraumatic stress symptoms were reduced in military
service members following the mindfulness-based integrative medicine program; however,
Stress, Sleep, and Inflammation
43
this program required almost 30 treatment hours. This may be an excessive treatment
duration when mindfulness meditation is used in populations with less severe symptoms.
As such, Study IV investigated the effect of a brief 5-week (7.5-hour) mindfulness-based
program on perceived stress symptoms in moderately stressed healthcare professionals.
Results indicated that the meditation group had larger reductions in perceived stress and
anxiety compared with the control group, and these reductions were maintained two months
following the completion of the program. At present there are no recognized minimal
clinically important difference scores for the PSS-10 (perceived stress) or the VAS-A
(anxiety).
c
However, normative data from 2009 reported mean PSS-10 scores of 19.11 in
high-stress groups and 11.09 in low-stress groups.220 In our meditation group, PSS-10
scores reduced from 19.63 to 13.30 over the course of the study. Thus, we can extrapolate
that the participants had some clinically meaningful level of stress reduction, although their
levels may not have reached the threshold of low stress. However, it’s worth noting that the
participants were self-motivating volunteers and may have been prone to an expectancy
bias, which could have influenced the between-group effects.
d
We also found no significant
between-group differences in burnout (i.e., emotional exhaustion and depersonalization),
which may have been due to a floor effect since the participants did not present with high
levels of burnout to begin with. Moreover, the use of the abridged 2-item MBI may not
have captured the presentation of burnout in this population.
Typical mindfulness-based programs are around 30 hours in duration and include a full-day
silent meditation retreat. This can be cost prohibitive and impractical to implement during
the workday in a bustling healthcare setting.221 When mindfulness-based programs are
below four hours, the benefits are inconclusive.221 In the current mindfulness-based
program, classes filled up within three days of the announcement, which was a proxy for
community interest. The overall quality of the program was rated as ‘very good’ or
‘excellent’ by 97% of the meditation participants. No adverse events were reported and the
attrition rate of 19% was consistent with the literature for comparable populations.222 As
such, these findings suggest that a brief 5-week (7.5-hour) mindfulness-based program is
feasible and effective at reducing perceived stress and anxiety in healthcare professionals.
c
The minimal clinically important difference (MCID) defines the smallest amount an outcome must change to
be meaningful to the patient. An outcome’s change can be statistically significant and not meet the MICD.
d
Expectancy bias is a type of cognitive bias that occurs when a participant expects a certain result and
therefore unconsciously manipulates an experiment or reports the expected result.
Heather L Rusch
44
5.5 GENERAL METHODOLOGICAL CONSIDERATIONS
This thesis had a number of strengths and limitations; the main methodological
considerations are discussed below, and a comprehensive account can be found in the
corresponding manuscripts (see Chapter 9. Appendix). The first methodological
consideration involves the inclusion/exclusion of randomized controlled trials. Randomized
controlled trials are the gold standard for evaluating the effectiveness of an intervention.
Herein, groups of similar people are randomly assigned to an experimental group or to a
control group; the outcome variable of interest is the only expected difference between the
two groups. However, due to ethical, feasibility, and financial reasons this study design is
sometimes not a viable option. In Study II, we only included randomized controlled trials in
the meta-analysis that compared mindfulness meditation to evidence-based sleep treatments
or to time/attention matched placebo controls. This provided greater confidence that the
reported benefits of mindfulness meditation were not due to nonspecific effects.
e
In Study
IV, we randomized participants to either a meditation experimental group or a life-as-usual
control group. Including an active control group would have strengthened our study;
however, there is no consensus on what constitutes an ideal active control group for
mindfulness meditation in non-clinical populations. Sham mindfulness meditation has been
used with success for very short interventions (20 to 30 minutes).223 However,
administering sham mindfulness meditation for longer programs over multiple sessions
becomes challenging. In 2012, researchers attempted to validate the Health Enhancement
Program (HEP) as an acceptable active control group for mindfulness mediation; herein all
components of MBSR are matched in the HEP control group with the exception of
mindfulness.224 While these types of studies are critical in evaluating the effectiveness of
mindfulness meditation, they can be costly and timely to implement. For ethical reasons,
Study I and Study III were not randomized controlled trials (it is unethical to deny
treatment to symptomatic active duty military), thus we were limited in the conclusions we
could make regarding the treatment effects for these studies.
One way we attempted to compensate for the single-arm designs in Study I and Study III
was to minimize clinical heterogeneity. Clinical heterogeneity arises from differences in
participant demographics (e.g., sex, age, race), clinical characteristics (e.g., symptom
e
Nonspecific effects are the indirect benefits of the treatment, such as placebo effects and indirect benefits
from the healthcare providers’ time and attention toward the participants.
Stress, Sleep, and Inflammation
45
severity, comorbidities), and intervention characteristics (e.g., type, duration, frequency,
dose). This variability can lead to inaccurate conclusions and in turn mislead decision-
makers and other researchers. The participants in Study I and Study III were mostly white
men under 57 years of age. Both studies were also comprised of military service members
with sleep disturbance and neurobehavioral symptoms. However, in Study I the most
conservative cut-points were used to create well-characterized groups of participants with
and without PTSD. This allowed us to determine the differentially expressed genes that
were specific to posttraumatic stress symptoms and symptom reduction with enhanced
precision. In Study III, there was much greater heterogeneity in symptom severity and
comorbidity. While most participants had some degree of neurobehavioral symptoms, only
47 to 87% met criteria for a provisional diagnosis for at least one mental health condition
(range dependent on the condition, see Table 6). This may have masked changes in IL-6
and IL-10 over time that could have been linked to the improvement of a specific symptom
or condition. Lastly, there was unintended heterogeneity in the intervention characteristics.
In Study I, the participants were assigned a standardized sleep treatment based on their
diagnosed sleep disorder; however, there was such a high noncompliance rate (66.7%) for
the APAP therapy, it was difficult to draw any conclusions regarding treatment effects
except that the APAP therapy was not feasible in participants with PTSD. In Study III, the
participants, in collaboration with their practitioner, designed their own treatment plan; this
personalized medicine approach is at the heart of integrative medicine but precluded us
from testing for specific intervention effects.
While clinical homogeneity has its strengths, it should be balanced with generalizability.
Generalizability is the extent to which the conclusions of a study can be applied to broader
groups of people and settings. Even though Study II had very strict inclusion/exclusion
criteria when it came to intervention types and comparison groups, we were liberal in
including all adult populations provided they had clinically relevant sleep disturbance and
were not expert meditators (see Table 3). Since the final meta-analysis included adults with
an array of mental and physical health conditions, there is greater confidence that the
findings can be extended to other groups with sleep disturbance beyond those that were
included in our study. Study I and Study III are limited in their ability to generalize the
findings to women, civilians, and other non-military trauma types. Likewise, in Study IV,
the results may not generalize to men, lower educational levels, or other institutes that do
not value or emphasize the benefits of supporting employee health and wellness.
Heather L Rusch
46
5.6 CLINICAL IMPLICATIONS & FUTURE DIRECTIONS
PTSD can be difficult to diagnose because it shares symptoms with other mental and
physical health conditions. When PTSD is misdiagnosed, patients do not receive the correct
treatment, which can be inefficient and harmful. In Study I, we investigated what symptoms
could genetically differentiate participants with PTSD from those without PTSD and found
that intrusion symptoms accounted for almost all of the gene expression differences.
Additionally, we found that intrusion symptoms were linked to increased expression of
immune response genes, which were normalized with symptom reduction. This highlights
the importance of focusing on the intrusion symptom cluster for precision medicine
initiatives in individuals with PTSD. Since Study I was initiated, more advanced gene
expression technologies like RNA sequencing are now available that are able to identify
both known and unknown genes. A significant body of literature has also demonstrated that
the protein and microRNA constituents of exosomes (small extracellular vesicles) hold
promise as novel biomarkers for PTSD (Paper 5).225 This unveils exciting opportunities for
improving diagnostics in trauma-exposed populations. Our ultimate goal is to design
biomarker-based tests that will not only predict who will develop PTSD following a
traumatic event but will also identify the most effective treatment for a given individual.
Another avenue to help decrease the risk for PTSD and increase the effectiveness of
treatments is through the early identification and treatment of sleep disturbance in trauma-
exposed populations. At present, there is no consensus about incorporating evidence-based
sleep treatments into standard of care for the prevention or management of PTSD;
importantly, there are no empirical data available to establish the order in which sleep and
PTSD treatments should be delivered.226 One recent pilot study examined the delivery of
CBT-I prior to trauma-focused psychotherapy in veterans and reported large decreases in
insomnia and posttraumatic stress symptoms, and large increases in quality of life.227
Moreover, clinicians need to be aware that sleep disturbance can diminish the efficacy of
trauma-focused psychotherapy, especially when they rely on memory extinction and
consolidation processes.99,228 Future studies might establish the efficacy of integrative
medicine approaches that address sleep disturbances and posttraumatic stress symptoms
simultaneously. For example, Study III combined soporific mindfulness practices with art
therapy, which has a putative effect on PTSD trauma processing.229 Lastly, while APAP
therapy may be more challenging for individuals with PTSD, research has found that
enhanced self-efficacy can help increase compliance.230
Stress, Sleep, and Inflammation
47
In addition to evidence-based sleep treatments, alternative interventions that target multiple
biological systems may offer additional benefits to individuals with stress-related disorders.
Current first-line treatments for PTSD target psychological symptoms; however, the
presence of immune response genes (Study I) suggests a need for a more comprehensive
treatment approach to address the potential influences of immune dysregulation on emotion
and behavior.231,232 It is possible that the growing interest in alternative therapies for PTSD
such as meditation, yoga, and other interventions that increase physical activity or alter
dietary intake may provide benefits through their anti-inflammatory effects.233-236 To date,
at least 20 clinical trials have investigated the antidepressant activity of anti-inflammatory
treatments on depressive symptoms in individuals with chronic inflammatory conditions.237
Many of these trials reported significant reductions in symptoms of depression, which
prompted a new series of clinical trials specifically designed to evaluate the safety and
efficacy of anti-inflammatory therapeutics in mood disorders.238 This research opens up a
new line of investigation for novel therapeutics that directly target inflammation in
individuals with PTSD, which could potentially result in improved mental and physical
outcomes. Future research would also benefit from empirical studies that examine the
relationship between posttraumatic stress symptoms and inflammation dimensionally
(along a spectrum from low to high) as outlined by the Research Domain Criteria.
Lastly, mindfulness meditation may be beneficial to reduce perceived stress, which could
potentially prevent the development of more severe mental and physical health conditions.
In Study IV, the 7.5-hour mindfulness-based program was a feasible and effective level of
training to reduce stress and anxiety in busy healthcare professionals. When stress is left
unchecked it can increase the risk for burnout (see Figure 1). A systematic review of 36
prospective trials found that burnout was a significant predictor of developing the following
physical health conditions: cardiovascular disease, hypercholesterolemia, type 2 diabetes,
respiratory issues, gastrointestinal problems, musculoskeletal pain, headaches, prolonged
fatigue, and mortality under 45 years of age.239 Moreover, burnout increased the risk of
developing insomnia, being hospitalized for a psychiatric disorder, and being prescribed
psychotropic and antidepressant medications.239 Burnout not only affects the individual, but
has been associated with decreased productivity, suboptimal patient care, and increased
medical errors.240 To help ensure the safety of both provider and patient, organizations
should work towards implementing feasible and effective interventions to build resilience
in healthcare professionals, so they can better manage occupational challenges.
Heather L Rusch
48
If I have seen further,
It is by standing upon the shoulders of giants.
― Sir Isaac Newton
Stress, Sleep, and Inflammation
49
6 CONCLUSIONS
The findings of these four studies led to some important conclusions regarding the link
between stress, sleep, and inflammation that may inform the development of enhanced
treatments for populations with stress-related symptoms and disorders. In Study II, while
mindfulness research is still in its infancy, our preliminary results suggest that mindfulness
meditation is effective in improving sleep in adult populations with various mental and
physical health conditions. Less intense mindfulness meditation programs (7.5 hours) may
be beneficial to reduce perceived stress, which could potentially prevent the development of
more severe mental health conditions (Study IV). While 22.6% of individuals with PTSD
had reduced posttraumatic stress symptoms following standardized sleep therapy (Study I),
65.8% of individuals with PTSD had reduced posttraumatic stress symptoms following the
mindfulness-based integrative medicine program (Study III). There was some evidence that
a relationship exists between sleep quality improvements, decreases in gene expression
levels of inflammation, and reductions in posttraumatic stress symptoms; although the
direction of causality could not be determined (Study I and III). Despite these findings, the
potential mediating role of inflammation between sleep disturbance and posttraumatic
stress symptoms is still unclear. Future research would profit from addressing the
outstanding methodological design limitations, in addition to testing for sex differences,
and using a combination of objective and subjective measures of sleep in concert with
molecular and protein biomarker assessments. The field of mindfulness and
psychoneuroimmunology present great opportunities for therapeutic discovery to increase
resilience to buffer stress-elicited changes in physiology including immune responses.
Heather L Rusch
50
A human being is a part of the whole, called by us “Universe”, a part limited in time and
space. He experiences himself, his thoughts, and feelings as something separated from the
rest—a kind of optical delusion of his consciousness. This delusion is a kind of prison for
us, restricting us to our personal desires and to affection for a few persons nearest to us.
Our task must be to free ourselves from this prison by widening our circle of compassion to
embrace all living creatures and the whole of nature in its beauty. Nobody is able to
achieve this completely, but the striving for such achievement is in itself a part of the
liberation and a foundation for inner security.
― Albert Einstein
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7 ACKNOWLEDGEMENTS
Completing a PhD is a challenging journey with many unexpected turns, twists, and
setbacks. In fact, an alarming 50% of doctoral students leave graduate school without
finishing. However, completing a PhD across two countries, during a pandemic, as the
General Data Protection Regulation (GDPR) went into effect—prohibiting the transfer of
data and specimens between Europe and the United States—required a whole new level of
determination and resilience. This thesis is a testament that I have defeated the odds, but not
without a tremendous amount of support and guidance.
To my supervisors: Jessica Gill, you have given me the freedom to explore, the freedom to
grow, the freedom to do things my way…and to make mistakes in the process. You cooked
for me, you laughed with me, and you fought for me. I am so grateful to have had you as a
leader all these years. Julie Lasselin and Mats Lekander, you accepted me into your lab at
the 11th hour—four years crammed into two. A mission not for the faint-hearted, but we did
it—because of you. You are model scientists and lead by example; thank you for helping
me to learn more about psychoneuroimmunology and also about myself.
To my mentors, past and present: Anlys Olivera, Ann Berger, Christian Grillion, Emily
Holmes, Janet Clark, Johan Lundström, Monique Ernst, Pam Tamez, Pat Sokolove,
Paule Joseph, Rezvan Ameli, Sheila Rauch, Stal Shrestha, and Yuval Neria, you gave me
the space and platform to express and implement my ideas—reflecting back to me
confidence, hope, and excitement. I would leave our meetings feeling inspired, like I could
take on the world, and strapped with a new set of resources to do so. Even when things did
not work out as planned—which was often—you’d say to me, “I expect you to land on your
feet.” And I always did. Thank you for believing in me.
To my co-authors on the thesis papers: Anlys Olivera, Ann Berger, Amanda Jiang, Chris
Brewin, Christiana Martin, Colin West, Jeffrey Robinson, Jessica Gill, Julie Lasselin,
Lisa Levison, María José Luna, Mats Lekander, Michael Rosario, Michael Zoosman,
Nicole Osier, Ninet Sinaii, Rezvan Ameli, Samin Panahi, Sijung Yun, Thaddeus Haight,
Thomas DeGraba, Tianxia Wu, Vivian Guedes, and Whitney Livingston, I think it’s fair
to say that I would have four less publications if it weren’t for you all. You double checked,
triple checked, and sometimes even quadruple checked. You entertained my debates—and
often times won. The deadlines were tight, the analyses changed, and changed, and changed
again. Yet you were patient, flexible, detailed, and insightful—I appreciate you.
Heather L Rusch
52
To my functional MRI, bioinformatics, and statistical support: Madhav Goyal, Ninet
Sinaii, Sijung Yun, Thaddeus Haight, Tianxia Wu, and Wen-Tung Wang, an average
teacher tells, a good teacher explains, a superior teacher demonstrates; however, it is the
great teacher that inspires through their love of the subject and passion for excellence.
Thank you for your time, patience, dedication, and for awakening a joy for analysis in me.
To my thesis reviewers: Mom, Dad, Amanda Jiang, Anlys Olivera, Christina Devoto,
Isaac Barnes, Ninet Sinaii, Salvatore Torrisi, Sheila Rauch, and Vivian Guedes. All these
extremely busy and intelligent people willfully volunteered to review my thesis, so I would
not memorialize any blunders. I know you all had better things to do—I owe you big!
To my Brain Injury Unit labmates and beyond: Adewole, Amanda, Anlys, Cassie,
Candance, Christina, Delia, Emma, Julian, Michael, Nicholas, Pedro, Rebekah, Ruel,
Sara, Vida, Vivian, and Whitney, you are some of the finest people I know. Together we
lamented the fickle functioning of SIMOA®, got frostbite from pulling samples from the -
80°C freezer, then culminated the week with 1.5 hours of Iyengar yoga. My days (and
nights) were enriched because of the deep friendships we shared, both inside and outside of
work. Mary, it has been an honor to work alongside a nurse with your expertise and
integrity—everything just seemed to flow with you. Jerri and Precious your solid
administrative support made traveling between the US and Sweden as smooth as could be.
To my Section on Neurobiology of Fear and Anxiety labmates: Adam, Adrienne, Amanda,
Camille, Claudie, Emily, Salvatore (Sam), Sara, and Tiffany, I’ll always remember
scanning late night on the 7-Tesla, Society for Neuroscience, AFNI Bootcamp, teatime and
method tutorials with Sam, and Ethiopian takeout on Emily’s rooftop. I will probably never
work with 7-Tesla again, but our lasting friendships made this ‘detour’ all the worthwhile.
To my Sleepy Brain labmates: Gustav, Jimmy, Paola, Poyan, Sanna, and Vivian, you
welcomed me into the lab and into your beautiful country, notwithstanding my American
propensity for chit-chat. I was repatriated so abruptly—to be continued, there is still so
much more to explore.
To the participants: Madigan Army Medical Center, National Institutes of Health, and
Walter Reed National Military Medical Center, thank you for your time, effort, and
willingness to share your experience. Without you, this research would not be possible.
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To my Vipassanā meditators: Dennis Ferman, Sharat Jain, Sudha Jain, and my dhamma
brothers and sisters, because of your wisdom, karuṇā, and mettā there will always be light.
May you all be happy. May you all be peaceful. May you all be liberated.
To my friends who have become like family: Angie, Anthony, Christopher, Eduardo,
Ekat, Elena, Joseph, Kristin, Natalia, Omer, Pia, Sonia, Vincent, Vineet, and Vinod, I’ve
known most of you since I was a crazy kid—discovering life…sometimes lost, sometimes
found. Through everything you have been a positive source of energy, encouraging me to
go after my dreams, applauding my victories, and listening to me go on and on about my
research. Anthony, I have an absurdly high Almetric score on my publications because you
never fail to share my science with your massive social media network—love having you as
my #1 fan. Joseph, you whisked me away to Joshua Tree when my first three studies
flopped, so I could sleep under the moon and recharge in nature. Then you sent me a
monthly subscription of avocados while I was drafting my thesis—no wonder you’re my
bestie. Kristin, you have a special knack for reminding me to laugh and not to take life too
seriously. Pia, thank you for being my Scandinavian POC, my Swedish tour guide, and for
making my birthday in Copenhagen so special—you always take such good care of me.
Vincent, so grateful to venture on our journeys together…growing and changing and
encouraging each other along the way. Vineet, thank you for supporting me during the most
challenging times when everything seemed to be falling apart. Small things like getting me
the high-speed modem/router, so I could work faster from home or shipping the space
heater to my NIH office, so I would stay warm made all the difference during those times.
Vinod, you found me not one, but two large cans of Lysol during the height of the
pandemic, went food shopping for me when I couldn’t risk getting sick due to tight defense
deadlines, and have been an invaluable source of emotional support—I appreciate you.
To my family: Grandma, Grandpa, Nanny, my amazing aunts, uncles, cousins, in-laws,
and niece, life is beautiful because of you! Milton, thank you for the countless times you
picked me up from the airport; love having you in DC with me. Mom and Dad, how could I
possibly thank you enough—you created me with love and gave me perseverance in spades.
Milt Campbell, I never cheated the journey…
Heather L Rusch
54
My brain is only a receiver,
In the Universe there is a core from which we obtain knowledge, strength, and inspiration.
I have not penetrated into the secrets of this core,
But I know that it exists.
― Nikola Tesla
Stress, Sleep, and Inflammation
55
8 REFFERENCES
1. Yehuda R, Hoge CW, McFarlane AC, et al. Post-traumatic stress disorder. Nature
Reviews Disease Primers. 2015:15057.
2. Southwick SM, Sippel L, Krystal J, Charney D, Mayes L, Pietrzak R. Why are some
individuals more resilient than others: the role of social support. World Psychiatry.
2016;15(1):77-79.
3. Haagsma JA, Polinder S, Olff M, Toet H, Bonsel GJ, van Beeck EF. Posttraumatic
stress symptoms and health-related quality of life: a two year follow up study of
injury treated at the emergency department. BMC Psychiatry. 2012;12:1.
4. Selye H. Stress and the general adaptation syndrome. Br Med J. 1950;1(4667):1383-
1392.
5. Fink G. Selye's general adaptation syndrome: stress-induced gastro-duodenal
ulceration and inflammatory bowel disease. J Endocrinol. 2017;232(3):F1-F5.
6. Szabo S, Yoshida M, Filakovszky J, Juhasz G. "Stress" is 80 Years Old: From Hans
Selye Original Paper in 1936 to Recent Advances in GI Ulceration. Curr Pharm Des.
2017;23(27):4029-4041.
7. Mason JW. A review of psychoendocrine research on the sympathetic-adrenal
medullary system. Psychosom Med. 1968;30(5):Suppl:631-653.
8. Levi L. Society, stress, and disease. WHO Chron. 1971;25(4):168-178.
9. Selye H. Stress without Distress. Philadelphia: J. B. Lippincott Co. ; 1974.
10. McEwen BS, Wingfield JC. The concept of allostasis in biology and biomedicine.
Horm Behav. 2003;43(1):2-15.
11. McEwen BS. Protective and damaging effects of stress mediators: central role of the
brain. Dialogues Clin Neurosci. 2006;8(4):367-381.
12. de Kloet ER, Joels M, Holsboer F. Stress and the brain: from adaptation to disease.
Nat Rev Neurosci. 2005;6(6):463-475.
13. Joels M, Baram TZ. The neuro-symphony of stress. Nat Rev Neurosci.
2009;10(6):459-466.
14. Kraynak TE, Marsland AL, Wager TD, Gianaros PJ. Functional neuroanatomy of
peripheral inflammatory physiology: A meta-analysis of human neuroimaging
studies. Neurosci Biobehav Rev. 2018;94:76-92.
15. Tank AW, Lee Wong D. Peripheral and central effects of circulating catecholamines.
Compr Physiol. 2015;5(1):1-15.
Heather L Rusch
56
16. Godoy LD, Rossignoli MT, Delfino-Pereira P, Garcia-Cairasco N, de Lima Umeoka
EH. A Comprehensive Overview on Stress Neurobiology: Basic Concepts and
Clinical Implications. Front Behav Neurosci. 2018;12:127.
17. Glaser R, Kiecolt-Glaser JK. Stress-induced immune dysfunction: implications for
health. Nat Rev Immunol. 2005;5(3):243-251.
18. McEwen BS, Bowles NP, Gray JD, et al. Mechanisms of stress in the brain. Nat
Neurosci. 2015;18(10):1353-1363.
19. McEwen BS. Protective and damaging effects of stress mediators: central role of the
brain. Prog Brain Res. 2000;122:25-34.
20. Cohen S, Janicki-Deverts D, Doyle WJ, et al. Chronic stress, glucocorticoid receptor
resistance, inflammation, and disease risk. Proc Natl Acad Sci U S A.
2012;109(16):5995-5999.
21. Cohen S, Janicki-Deverts D, Miller GE. Psychological stress and disease. JAMA.
2007;298(14):1685-1687.
22. Zorn JV, Schur RR, Boks MP, Kahn RS, Joels M, Vinkers CH. Cortisol stress
reactivity across psychiatric disorders: A systematic review and meta-analysis.
Psychoneuroendocrinology. 2017;77:25-36.
23. Dantzer R. Neuroimmune Interactions: From the Brain to the Immune System and
Vice Versa. Physiol Rev. 2018;98(1):477-504.
24. Dantzer R, O'Connor JC, Freund GG, Johnson RW, Kelley KW. From inflammation
to sickness and depression: when the immune system subjugates the brain. Nat Rev
Neurosci. 2008;9(1):46-56.
25. McEwen BS. Neurobiological and Systemic Effects of Chronic Stress. Chronic Stress
(Thousand Oaks). 2017;1.
26. Roozendaal B, McEwen BS, Chattarji S. Stress, memory and the amygdala. Nat Rev
Neurosci. 2009;10(6):423-433.
27. Schwabe L, Joels M, Roozendaal B, Wolf OT, Oitzl MS. Stress effects on memory:
an update and integration. Neurosci Biobehav Rev. 2012;36(7):1740-1749.
28. Freudenberger HJ. Staff Burn-Out. Journal of Social Issues. 1974;30(1):159-165.
29. Maslach C, Jackson SE, Leiter MP. Maslach burnout inventory manual. 3rd ed. Palo
Alto, Calif. (577 College Ave., Palo Alto 94306): Consulting Psychologists Press;
1996.
30. Bruce LC, Heimberg RG, Blanco C, Schneier FR, Liebowitz MR. Childhood
maltreatment and social anxiety disorder: implications for symptom severity and
response to pharmacotherapy. Depress Anxiety. 2012;29(2):131-138.
Stress, Sleep, and Inflammation
57
31. Dunlop BW, Wong A. The hypothalamic-pituitary-adrenal axis in PTSD:
Pathophysiology and treatment interventions. Prog Neuropsychopharmacol Biol
Psychiatry. 2019;89:361-379.
32. Hemmingsson E. Early Childhood Obesity Risk Factors: Socioeconomic Adversity,
Family Dysfunction, Offspring Distress, and Junk Food Self-Medication. Curr Obes
Rep. 2018;7(2):204-209.
33. Milivojevic V, Sinha R. Central and Peripheral Biomarkers of Stress Response for
Addiction Risk and Relapse Vulnerability. Trends Mol Med. 2018;24(2):173-186.
34. Crocq MA, Crocq L. From shell shock and war neurosis to posttraumatic stress
disorder: a history of psychotraumatology. Dialogues Clin Neurosci. 2000;2(1):47-55.
35. Association AP. Diagnostic and statistical manual of mental disorders. 3rd Edition
ed. Arlington, VA: American Psychiatric Association; 1980.
36. Bryant RA. Post-traumatic stress disorder: a state-of-the-art review of evidence and
challenges. World Psychiatry. 2019;18(3):259-269.
37. Steenkamp MM. True Evidence-Based Care for Posttraumatic Stress Disorder in
Military Personnel and Veterans. JAMA Psychiatry. 2016;73(5):431-432.
38. Yehuda R, Hoge CW. The Meaning of Evidence-Based Treatments for Veterans With
Posttraumatic Stress Disorder. JAMA Psychiatry. 2016;73(5):433-434.
39. Diagnostic and statistical manual of mental disorders. 5th ed. ed. Arlington, VA:
American Psychiatric Publishing; 2013.
40. Organization WH. International classification of diseases for mortality and morbidity
statistics. Vol 11th Revision: World Health Organization; 2018.
41. Cloitre M, Garvert DW, Brewin CR, Bryant RA, Maercker A. Evidence for proposed
ICD-11 PTSD and complex PTSD: a latent profile analysis. European journal of
psychotraumatology. 2013;4.
42. Maercker A, Brewin CR, Bryant RA, et al. Diagnosis and classification of disorders
specifically associated with stress: proposals for ICD-11. World Psychiatry.
2013;12(3):198-206.
43. Hansen M, Hyland P, Armour C, Shevlin M, Elklit A. Less is more? Assessing the
validity of the ICD-11 model of PTSD across multiple trauma samples. European
journal of psychotraumatology. 2015;6:28766.
44. Shevlin M, Hyland P, Vallieres F, et al. A comparison of DSM-5 and ICD-11 PTSD
prevalence, comorbidity and disability: an analysis of the Ukrainian Internally
Displaced Person's Mental Health Survey. Acta Psychiatr Scand. 2018;137(2):138-
147.
Heather L Rusch
58
45. Wisco BE, Marx BP, Miller MW, et al. A comparison of ICD-11 and DSM criteria
for posttraumatic stress disorder in two national samples of U.S. military veterans. J
Affect Disord. 2017;223:17-19.
46. Brewin CR, Cloitre M, Hyland P, et al. A review of current evidence regarding the
ICD-11 proposals for diagnosing PTSD and complex PTSD. Clin Psychol Rev.
2017;58:1-15.
47. Franklin CL, Walton JL, Cuccurullo LA, et al. Examining potential overlap of DSM-
5 PTSD criteria D and E. Psychiatry Res. 2016;246:250-254.
48. Hoge CW, Yehuda R, Castro CA, et al. Unintended Consequences of Changing the
Definition of Posttraumatic Stress Disorder in DSM-5: Critique and Call for Action.
JAMA Psychiatry. 2016;73(7):750-752.
49. Hyland P, Shevlin M, McNally S, Murphy J, Hansen M, Elklit A. Exploring
differences between the ICD-11 and DSM-5 models of PTSD: Does it matter which
model is used? J Anxiety Disord. 2016;37:48-53.
50. Stein DJ, McLaughlin KA, Koenen KC, et al. DSM-5 and ICD-11 definitions of
posttraumatic stress disorder: investigating "narrow" and "broad" approaches.
Depress Anxiety. 2014;31(6):494-505.
51. Galatzer-Levy IR, Bryant RA. 636,120 Ways to Have Posttraumatic Stress Disorder.
Perspect Psychol Sci. 2013;8(6):651-662.
52. Karam EG, Friedman MJ, Hill ED, et al. Cumulative traumas and risk thresholds: 12-
month PTSD in the World Mental Health (WMH) surveys. Depress Anxiety.
2014;31(2):130-142.
53. Kessler RC, Rose S, Koenen KC, et al. How well can post-traumatic stress disorder
be predicted from pre-trauma risk factors? An exploratory study in the WHO World
Mental Health Surveys. World Psychiatry. 2014;13(3):265-274.
54. Liu H, Petukhova MV, Sampson NA, et al. Association of DSM-IV Posttraumatic
Stress Disorder With Traumatic Experience Type and History in the World Health
Organization World Mental Health Surveys. JAMA Psychiatry. 2017;74(3):270-281.
55. Dursa EK, Reinhard MJ, Barth SK, Schneiderman AI. Prevalence of a positive screen
for PTSD among OEF/OIF and OEF/OIF-era veterans in a large population-based
cohort. J Trauma Stress. 2014;27(5):542-549.
56. Kessler RC, Sonnega A, Bromet E, Hughes M, Nelson CB. Posttraumatic stress
disorder in the National Comorbidity Survey. Arch Gen Psychiatry.
1995;52(12):1048-1060.
Stress, Sleep, and Inflammation
59
57. Shalev A, Liberzon I, Marmar C. Post-Traumatic Stress Disorder. N Engl J Med.
2017;376(25):2459-2469.
58. Sareen J, Cox BJ, Stein MB, Afifi TO, Fleet C, Asmundson GJ. Physical and mental
comorbidity, disability, and suicidal behavior associated with posttraumatic stress
disorder in a large community sample. Psychosom Med. 2007;69(3):242-248.
59. O'Donovan A, Cohen BE, Seal KH, et al. Elevated risk for autoimmune disorders in
iraq and afghanistan veterans with posttraumatic stress disorder. Biol Psychiatry.
2015;77(4):365-374.
60. Pacella ML, Hruska B, Delahanty DL. The physical health consequences of PTSD
and PTSD symptoms: a meta-analytic review. J Anxiety Disord. 2013;27(1):33-46.
61. Sommer JL, El-Gabalawy R, Mota N. Understanding the association between
posttraumatic stress disorder characteristics and physical health conditions: A
population-based study. J Psychosom Res. 2019;126:109776.
62. Song H, Fall K, Fang F, et al. Stress related disorders and subsequent risk of life
threatening infections: population based sibling controlled cohort study. BMJ.
2019;367:l5784.
63. Boyle E, Cancelliere C, Hartvigsen J, Carroll LJ, Holm LW, Cassidy JD. Systematic
review of prognosis after mild traumatic brain injury in the military: results of the
International Collaboration on Mild Traumatic Brain Injury Prognosis. Arch Phys
Med Rehabil. 2014;95(3 Suppl):S230-237.
64. Siegel JM. Clues to the functions of mammalian sleep. Nature. 2005;437(7063):1264-
1271.
65. Benveniste H, Lee H, Volkow ND. The Glymphatic Pathway: Waste Removal from
the CNS via Cerebrospinal Fluid Transport. Neuroscientist. 2017;23(5):454-465.
66. Zielinski MR, McKenna JT, McCarley RW. Functions and Mechanisms of Sleep.
AIMS Neurosci. 2016;3(1):67-104.
67. Liu TZ, Xu C, Rota M, et al. Sleep duration and risk of all-cause mortality: A flexible,
non-linear, meta-regression of 40 prospective cohort studies. Sleep Med Rev.
2017;32:28-36.
68. Yin J, Jin X, Shan Z, et al. Relationship of Sleep Duration With All-Cause Mortality
and Cardiovascular Events: A Systematic Review and Dose-Response Meta-Analysis
of Prospective Cohort Studies. J Am Heart Assoc. 2017;6(9).
69. Borbely AA, Daan S, Wirz-Justice A, Deboer T. The two-process model of sleep
regulation: a reappraisal. J Sleep Res. 2016;25(2):131-143.
Heather L Rusch
60
70. Besedovsky L, Lange T, Haack M. The Sleep-Immune Crosstalk in Health and
Disease. Physiol Rev. 2019;99(3):1325-1380.
71. Iber C, Ancoli-Israel, S., Chesson, A., & Quan, S. The AASM manual for the scoring
of sleep and associated events: rules, terminology, and technical specification.
Westchester, IL: American Academy of Sleep Medicine; 2017.
72. Irwin MR. Why sleep is important for health: a psychoneuroimmunology perspective.
Annu Rev Psychol. 2015;66:143-172.
73. Molle M, Bergmann TO, Marshall L, Born J. Fast and slow spindles during the sleep
slow oscillation: disparate coalescence and engagement in memory processing. Sleep.
2011;34(10):1411-1421.
74. Morgenthaler TI, Lee-Chiong T, Alessi C, et al. Practice parameters for the clinical
evaluation and treatment of circadian rhythm sleep disorders. An American Academy
of Sleep Medicine report. Sleep. 2007;30(11):1445-1459.
75. Perez-Pozuelo I, Zhai B, Palotti J, et al. The future of sleep health: a data-driven
revolution in sleep science and medicine. NPJ Digit Med. 2020;3:42.
76. Van de Water AT, Holmes A, Hurley DA. Objective measurements of sleep for non-
laboratory settings as alternatives to polysomnography--a systematic review. J Sleep
Res. 2011;20(1 Pt 2):183-200.
77. Aili K, Astrom-Paulsson S, Stoetzer U, Svartengren M, Hillert L. Reliability of
Actigraphy and Subjective Sleep Measurements in Adults: The Design of Sleep
Assessments. J Clin Sleep Med. 2017;13(1):39-47.
78. Caldwell BA, Redeker N. Sleep and trauma: an overview. Issues Ment Health Nurs.
2005;26(7):721-738.
79. Harvey AG, Tang NK. (Mis)perception of sleep in insomnia: a puzzle and a
resolution. Psychol Bull. 2012;138(1):77-101.
80. Boggero IA, Schneider VJ, 2nd, Thomas PL, Nahman-Averbuch H, King CD.
Associations of self-report and actigraphy sleep measures with experimental pain
outcomes in patients with temporomandibular disorder and healthy controls. J
Psychosom Res. 2019;123:109730.
81. Klein E, Koren D, Arnon I, Lavie P. Sleep complaints are not corroborated by
objective sleep measures in post-traumatic stress disorder: a 1-year prospective study
in survivors of motor vehicle crashes. J Sleep Res. 2003;12(1):35-41.
82. Ohayon MM, Shapiro CM. Sleep disturbances and psychiatric disorders associated
with posttraumatic stress disorder in the general population. Compr Psychiatry.
2000;41(6):469-478.
Stress, Sleep, and Inflammation
61
83. Ross RJ, Ball WA, Sullivan KA, Caroff SN. Sleep disturbance as the hallmark of
posttraumatic stress disorder. Am J Psychiatry. 1989;146(6):697-707.
84. Biddle DJ, Kelly PJ, Hermens DF, Glozier N. The association of insomnia with future
mental illness: is it just residual symptoms? Sleep Health. 2018;4(4):352-359.
85. Gehrman P, Seelig AD, Jacobson IG, et al. Predeployment Sleep Duration and
Insomnia Symptoms as Risk Factors for New-Onset Mental Health Disorders
Following Military Deployment. Sleep. 2013;36(7):1009-1018.
86. Pigeon WR, Campbell CE, Possemato K, Ouimette P. Longitudinal relationships of
insomnia, nightmares, and PTSD severity in recent combat veterans. J Psychosom
Res. 2013;75(6):546-550.
87. Spoormaker VI, Montgomery P. Disturbed sleep in post-traumatic stress disorder:
secondary symptom or core feature? Sleep Med Rev. 2008;12(3):169-184.
88. van Liempt S, van Zuiden M, Westenberg H, Super A, Vermetten E. Impact of
impaired sleep on the development of PTSD symptoms in combat veterans: a
prospective longitudinal cohort study. Depress Anxiety. 2013;30(5):469-474.
89. Wang HE, Campbell-Sills L, Kessler RC, et al. Pre-deployment insomnia is
associated with post-deployment post-traumatic stress disorder and suicidal ideation
in US Army soldiers. Sleep. 2019;42(2).
90. Hertenstein E, Feige B, Gmeiner T, et al. Insomnia as a predictor of mental disorders:
A systematic review and meta-analysis. Sleep Med Rev. 2019;43:96-105.
91. Koffel E, Polusny MA, Arbisi PA, Erbes CR. Pre-deployment daytime and nighttime
sleep complaints as predictors of post-deployment PTSD and depression in National
Guard troops. J Anxiety Disord. 2013;27(5):512-519.
92. Steenkamp MM, Schlenger WE, Corry N, et al. Predictors of PTSD 40 years after
combat: Findings from the National Vietnam Veterans longitudinal study. Depress
Anxiety. 2017;34(8):711-722.
93. Wright KM, Britt TW, Bliese PD, Adler AB, Picchioni D, Moore D. Insomnia as
predictor versus outcome of PTSD and depression among Iraq combat veterans. J
Clin Psychol. 2011;67(12):1240-1258.
94. Kobayashi I, Boarts JM, Delahanty DL. Polysomnographically measured sleep
abnormalities in PTSD: a meta-analytic review. Psychophysiology. 2007;44(4):660-
669.
95. Zhang Y, Ren R, Sanford LD, et al. Sleep in posttraumatic stress disorder: A
systematic review and meta-analysis of polysomnographic findings. Sleep Med Rev.
2019;48:101210.
Heather L Rusch
62
96. Elliott JE, Opel RA, Pleshakov D, et al. Post-traumatic stress disorder increases odds
of REM sleep behavior disorder and other parasomnias in Veterans with and without
comorbid traumatic brain injury. Sleep. 2019.
97. Germain A, James J, Insana S, et al. A window into the invisible wound of war:
functional neuroimaging of REM sleep in returning combat veterans with PTSD.
Psychiatry Res. 2013;211(2):176-179.
98. Mellman TA, Bustamante V, Fins AI, Pigeon WR, Nolan B. REM sleep and the early
development of posttraumatic stress disorder. Am J Psychiatry. 2002;159(10):1696-
1701.
99. Murkar ALA, De Koninck J. Consolidative mechanisms of emotional processing in
REM sleep and PTSD. Sleep Med Rev. 2018;41:173-184.
100. Ross RJ. The changing REM sleep signature of posttraumatic stress disorder. Sleep.
2014;37(8):1281-1282.
101. Medzhitov R. Origin and physiological roles of inflammation. Nature.
2008;454(7203):428-435.
102. Lasselin J, Elsenbruch S, Lekander M, et al. Mood disturbance during experimental
endotoxemia: Predictors of state anxiety as a psychological component of sickness
behavior. Brain Behav Immun. 2016;57:30-37.
103. Sankowski R, Mader S, Valdes-Ferrer SI. Systemic inflammation and the brain: novel
roles of genetic, molecular, and environmental cues as drivers of neurodegeneration.
Front Cell Neurosci. 2015;9:28.
104. Nievergelt CM, Ashley-Koch AE, Dalvie S, et al. Genomic Approaches to
Posttraumatic Stress Disorder: The Psychiatric Genomic Consortium Initiative. Biol
Psychiatry. 2018;83(10):831-839.
105. Yehuda R, Koenen KC, Galea S, Flory JD. The role of genes in defining a molecular
biology of PTSD. Dis Markers. 2011;30(2-3):67-76.
106. Merrick BA, Madenspacher JH. Complementary gene and protein expression studies
and integrative approaches in toxicogenomics. Toxicol Appl Pharmacol. 2005;207(2
Suppl):189-194.
107. Muhie S, Gautam A, Chakraborty N, et al. Molecular indicators of stress-induced
neuroinflammation in a mouse model simulating features of post-traumatic stress
disorder. Transl Psychiatry. 2017;7(5):e1135.
108. Enache D, Pariante CM, Mondelli V. Markers of central inflammation in major
depressive disorder: A systematic review and meta-analysis of studies examining
Stress, Sleep, and Inflammation
63
cerebrospinal fluid, positron emission tomography and post-mortem brain tissue.
Brain Behav Immun. 2019;81:24-40.
109. Agorastos A, Hauger RL, Barkauskas DA, et al. Circadian rhythmicity, variability
and correlation of interleukin-6 levels in plasma and cerebrospinal fluid of healthy
men. Psychoneuroendocrinology. 2014;44:71-82.
110. Agorastos A, Hauger RL, Barkauskas DA, et al. Relations of combat stress and
posttraumatic stress disorder to 24-h plasma and cerebrospinal fluid interleukin-6
levels and circadian rhythmicity. Psychoneuroendocrinology. 2019;100:237-245.
111. Lehrner A, Yehuda R. Biomarkers of PTSD: military applications and considerations.
European journal of psychotraumatology. 2014;5.
112. Banati RB, Newcombe J, Gunn RN, et al. The peripheral benzodiazepine binding site
in the brain in multiple sclerosis: quantitative in vivo imaging of microglia as a
measure of disease activity. Brain. 2000;123 ( Pt 11):2321-2337.
113. Miller MW, Lin AP, Wolf EJ, Miller DR. Oxidative Stress, Inflammation, and
Neuroprogression in Chronic PTSD. Harv Rev Psychiatry. 2018;26(2):57-69.
114. Mondelli V, Vernon AC, Turkheimer F, Dazzan P, Pariante CM. Brain microglia in
psychiatric disorders. Lancet Psychiatry. 2017;4(7):563-572.
115. Passos IC, Vasconcelos-Moreno MP, Costa LG, et al. Inflammatory markers in post-
traumatic stress disorder: a systematic review, meta-analysis, and meta-regression.
The Lancet Psychiatry. 2015;2(11):1002-1012.
116. Kiecolt-Glaser JK, Derry HM, Fagundes CP. Inflammation: depression fans the
flames and feasts on the heat. Am J Psychiatry. 2015;172(11):1075-1091.
117. Renna ME, O'Toole MS, Spaeth PE, Lekander M, Mennin DS. The association
between anxiety, traumatic stress, and obsessive-compulsive disorders and chronic
inflammation: A systematic review and meta-analysis. Depress Anxiety.
2018;35(11):1081-1094.
118. Sumner JA, Nishimi KM, Koenen KC, Roberts AL, Kubzansky LD. Posttraumatic
Stress Disorder and Inflammation: Untangling Issues of Bidirectionality. Biol
Psychiatry. 2020;87(10):885-897.
119. Breen MS, Tylee DS, Maihofer AX, et al. PTSD Blood Transcriptome Mega-
Analysis: Shared Inflammatory Pathways across Biological Sex and Modes of
Trauma. Neuropsychopharmacology. 2018;43(3):469-481.
120. Bryant PA, Trinder J, Curtis N. Sick and tired: Does sleep have a vital role in the
immune system? Nat Rev Immunol. 2004;4(6):457-467.
Heather L Rusch
64
121. Irwin MR, Olmstead R, Carroll JE. Sleep Disturbance, Sleep Duration, and
Inflammation: A Systematic Review and Meta-Analysis of Cohort Studies and
Experimental Sleep Deprivation. Biol Psychiatry. 2016;80(1):40-52.
122. Irwin MR, Wang M, Campomayor CO, Collado-Hidalgo A, Cole S. Sleep deprivation
and activation of morning levels of cellular and genomic markers of inflammation.
Arch Intern Med. 2006;166(16):1756-1762.
123. Irwin MR, Olmstead R, Breen EC, et al. Cognitive behavioral therapy and tai chi
reverse cellular and genomic markers of inflammation in late-life insomnia: a
randomized controlled trial. Biol Psychiatry. 2015;78(10):721-729.
124. Livingston WS, Rusch HL, Nersesian PV, Baxter T, Mysliwiec V, Gill JM. Improved
Sleep in Military Personnel is Associated with Changes in the Expression of
Inflammatory Genes and Improvement in Depression Symptoms. Front Psychiatry.
2015;6:59.
125. Clinical Practice Guideline for the Treatment of Posttraumatic Stress Disorder.
American Psychological Association; 2017.
126. Foa EB, Kozak MJ. Emotional processing of fear: exposure to corrective information.
Psychol Bull. 1986;99(1):20-35.
127. Rothbaum BO, Schwartz AC. Exposure therapy for posttraumatic stress disorder. Am
J Psychother. 2002;56(1):59-75.
128. Coventry PA, Meader N, Melton H, et al. Psychological and pharmacological
interventions for posttraumatic stress disorder and comorbid mental health problems
following complex traumatic events: Systematic review and component network
meta-analysis. PLoS Med. 2020;17(8):e1003262.
129. Steenkamp MM, Litz BT, Hoge CW, Marmar CR. Psychotherapy for Military-
Related PTSD: A Review of Randomized Clinical Trials. JAMA. 2015;314(5):489-
500.
130. Merz J, Schwarzer G, Gerger H. Comparative Efficacy and Acceptability of
Pharmacological, Psychotherapeutic, and Combination Treatments in Adults With
Posttraumatic Stress Disorder: A Network Meta-analysis. JAMA Psychiatry. 2019.
131. Rauch SAM, Kim HM, Powell C, et al. Efficacy of Prolonged Exposure Therapy,
Sertraline Hydrochloride, and Their Combination Among Combat Veterans With
Posttraumatic Stress Disorder: A Randomized Clinical Trial. JAMA Psychiatry.
2019;76(2):117-126.
132. Cannon WB. Bodily changes in pain, hunger, fear and rage: An account of recent
researches into the function of emotional excitement.: D Appleton & Company; 1915.
Stress, Sleep, and Inflammation
65
133. Irwin MR. Sleep and inflammation: partners in sickness and in health. Nat Rev
Immunol. 2019;19(11):702-715.
134. Zoccola PM, Dickerson SS. Assessing the relationship between rumination and
cortisol: a review. J Psychosom Res. 2012;73(1):1-9.
135. Imeri L, Opp MR. How (and why) the immune system makes us sleep. Nat Rev
Neurosci. 2009;10(3):199-210.
136. Irwin MR, Opp MR. Sleep Health: Reciprocal Regulation of Sleep and Innate
Immunity. Neuropsychopharmacology. 2017;42(1):129-155.
137. Wang Z, Caughron B, Young MRI. Posttraumatic Stress Disorder: An Immunological
Disorder? Front Psychiatry. 2017;8:222.
138. Gutner CA, Pedersen ER, Drummond SPA. Going direct to the consumer: Examining
treatment preferences for veterans with insomnia, PTSD, and depression. Psychiatry
Res. 2018;263:108-114.
139. Jansson-Frojmark M, Norell-Clarke A. Cognitive Behavioural Therapy for Insomnia
in Psychiatric Disorders. Curr Sleep Med Rep. 2016;2(4):233-240.
140. Wu JQ, Appleman ER, Salazar RD, Ong JC. Cognitive Behavioral Therapy for
Insomnia Comorbid With Psychiatric and Medical Conditions: A Meta-analysis.
JAMA Intern Med. 2015;175(9):1461-1472.
141. Muller F, M. The Dhammapada. http://www.sacred-texts.com/bud/sbe10/index.htm.
Published 1881. Accessed Aug 20, 2020.
142. Kabat-Zinn J. Wherever You Go, There You Are. New York, NY: Hyperion; 2004.
143. Goyal M, Singh S, Sibinga EMS, et al. Meditation programs for psychological stress
and well-being. Comparative Effectiveness Review. 2014;124:1-194.
144. Tang YY, Holzel BK, Posner MI. The neuroscience of mindfulness meditation. Nat
Rev Neurosci. 2015;16(4):213-225.
145. Desbordes G, Negi LT, Pace TW, Wallace BA, Raison CL, Schwartz EL. Effects of
mindful-attention and compassion meditation training on amygdala response to
emotional stimuli in an ordinary, non-meditative state. Frontiers in human
neuroscience. 2012;6:292.
146. Ong JC, Ulmer CS, Manber R. Improving sleep with mindfulness and acceptance: a
metacognitive model of insomnia. Behav Res Ther. 2012;50(11):651-660.
147. Jain S, Shapiro SL, Swanick S, et al. A randomized controlled trial of mindfulness
meditation versus relaxation training: effects on distress, positive states of mind,
rumination, and distraction. Ann Behav Med. 2007;33(1):11-21.
Heather L Rusch
66
148. van Vugt MK, Hitchcock P, Shahar B, Britton W. The effects of mindfulness-based
cognitive therapy on affective memory recall dynamics in depression: a mechanistic
model of rumination. Frontiers in human neuroscience. 2012;6:257.
149. Black DS, Slavich GM. Mindfulness meditation and the immune system: a systematic
review of randomized controlled trials. Ann N Y Acad Sci. 2016;1373(1):13-24.
150. Pascoe MC, Thompson DR, Jenkins ZM, Ski CF. Mindfulness mediates the
physiological markers of stress: Systematic review and meta-analysis. J Psychiatr
Res. 2017;95:156-178.
151. Kanen JW, Nazir RF, Sedky K, Basant PK. The Effects of Mindfulness-Based
Interventions on Sleep Disturbance: A Meta-Analysis. Adolescent Psychiatry.
2015;5(2):105-115.
152. Gong H, Ni CX, Liu YZ, et al. Mindfulness meditation for insomnia: A meta-analysis
of randomized controlled trials. J Psychosom Res. 2016;89:1-6.
153. Goyal M, Singh S, Sibinga EM, et al. Meditation programs for psychological stress
and well-being: a systematic review and meta-analysis. JAMA Intern Med.
2014;174(3):357-368.
154. Bell IR, Caspi O, Schwartz GE, et al. Integrative medicine and systemic outcomes
research: issues in the emergence of a new model for primary health care. Arch Intern
Med. 2002;162(2):133-140.
155. Weisfeld V. Summit on Integrative Medicine & The Health of the Public: Issue
Background and Overview. Paper presented at: Institute of Medicine2009;
Washington DC.
156. Madsen C, Vaughan M, Koehlmoos TP. Use of Integrative Medicine in the United
States Military Health System. Evid Based Complement Alternat Med.
2017;2017:9529257.
157. Gaudet TW, Snyderman R. Integrative medicine and the search for the best practice
of medicine. Acad Med. 2002;77(9):861-863.
158. Wolever RQ, Caldwell KL, McKernan LC, Hillinger MG. Integrative Medicine
Strategies for Changing Health Behaviors: Support for Primary Care. Prim Care.
2017;44(2):229-245.
159. Wilkins KC, Lang AJ, Norman SB. Synthesis of the psychometric properties of the
PTSD checklist (PCL) military, civilian, and specific versions. Depress Anxiety.
2011;28(7):596-606.
160. Using the PTSD Checklist (PCL). In. VA National Center for PTSD2012:1-3.
Stress, Sleep, and Inflammation
67
161. Edmondson D, von Känel R. Post-traumatic stress disorder and cardiovascular
disease. The Lancet Psychiatry. 2017;4(4):320-329.
162. Muller KE, Benignus VA. Increasing scientific power with statistical power.
Neurotoxicol Teratol. 1992;14(3):211-219.
163. Muller KE, Lavange LM, Ramey SL, Ramey CT. Power Calculations for General
Linear Multivariate Models Including Repeated Measures Applications. J Am Stat
Assoc. 1992;87(420):1209-1226.
164. Kredlow MA, Capozzoli MC, Hearon BA, Calkins AW, Otto MW. The effects of
physical activity on sleep: a meta-analytic review. J Behav Med. 2015;38(3):427-449.
165. Morgenthaler T, Kramer M, Alessi C, et al. Practice parameters for the psychological
and behavioral treatment of insomnia: an update. An american academy of sleep
medicine report. Sleep. 2006;29(11):1415-1419.
166. Owens DK, Lohr KN, Atkins D, et al. AHRQ series paper 5: grading the strength of a
body of evidence when comparing medical interventions--agency for healthcare
research and quality and the effective health-care program. J Clin Epidemiol.
2010;63(5):513-523.
167. Buysse DJ, Reynolds CF, 3rd, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh
Sleep Quality Index: a new instrument for psychiatric practice and research.
Psychiatry Res. 1989;28(2):193-213.
168. Hays RD, Martin SA, Sesti AM, Spritzer KL. Psychometric properties of the Medical
Outcomes Study Sleep measure. Sleep Med. 2005;6(1):41-44.
169. Morin CM, Belleville G, Belanger L, Ivers H. The Insomnia Severity Index:
psychometric indicators to detect insomnia cases and evaluate treatment response.
Sleep. 2011;34(5):601-608.
170. Review Manager (RevMan) [Computer program]. Version 5.3 Copenhagen
[computer program]. The Cochrane Collaboration2014.
171. Corrigan JD, Bogner J. Initial reliability and validity of the Ohio State University TBI
Identification Method. J Head Trauma Rehabil. 2007;22(6):318-329.
172. K.D. C, Kalmar K. Persistent postconcussion syndrome: the structure of subjective
complaints after mild traumatic brain injury. The Journal of head trauma
rehabilitation. 1995;10(3):1-17.
173. Spitzer RL, Kroenke K, Williams JB. Validation and utility of a self-report version of
PRIME-MD: the PHQ primary care study. Primary Care Evaluation of Mental
Disorders. Patient Health Questionnaire. Jama. 1999;282(18):1737-1744.
Heather L Rusch
68
174. Spitzer RL, Kroenke K, Williams JB, Lowe B. A brief measure for assessing
generalized anxiety disorder: the GAD-7. Arch Intern Med. 2006;166(10):1092-1097.
175. Wilson DH, Rissin DM, Kan CW, et al. The Simoa HD-1 Analyzer: A Novel Fully
Automated Digital Immunoassay Analyzer with Single-Molecule Sensitivity and
Multiplexing. J Lab Autom. 2016;21(4):533-547.
176. Sleep and Combat-Related Post Traumatic Stress Disorder. Vol 1. New York:
Springer-Verlag; 2018.
177. Cohen S, Kamarck T, Mermelstein R. A global measure of perceived stress. J Health
Soc Behav. 1983;24(4):385-396.
178. Cook-Cottone C, & Guyker, WM. The Development and Validation of the Mindful
Self-Care Scale (MSCS): An Assessment of Practice that Support Positive
Embodiment. Mindfulness. 2018;1(9):161-175.
179. Osman A, Lamis DA, Bagge CL, Freedenthal S, Barnes SM. The Mindful Attention
Awareness Scale: Further Examination of Dimensionality, Reliability, and
Concurrent Validity Estimates. J Pers Assess. 2016;98(2):189-199.
180. Watson D, Clark LA, Tellegen A. Development and validation of brief measures of
positive and negative affect: the PANAS scales. J Pers Soc Psychol.
1988;54(6):1063-1070.
181. Williams VS, Morlock RJ, Feltner D. Psychometric evaluation of a visual analog
scale for the assessment of anxiety. Health Qual Life Outcomes. 2010;8:57.
182. Yadama GN, Drake B. Confirmatory factor analysis of the Maslach Burnout
Inventory. Social Work Research. 1995;19(3):184-192.
183. Tests for Two Means in a Repeated Measures Design. In: Software PSS, ed: NCSS,
LLC.:1-23.
184. Gueorguieva R, Krystal JH. Move over ANOVA: progress in analyzing repeated-
measures data and its reflection in papers published in the Archives of General
Psychiatry. Arch Gen Psychiatry. 2004;61(3):310-317.
185. Adler E, Dhruva A, Moran PJ, et al. Impact of a Mindfulness-Based Weight-Loss
Intervention on Sleep Quality Among Adults with Obesity: Data from the SHINE
Randomized Controlled Trial. J Altern Complement Med. 2016;23(3):188-195.
186. Garland SN, Carlson LE, Stephens AJ, Antle MC, Samuels C, Campbell TS.
Mindfulness-based stress reduction compared with cognitive behavioral therapy for
the treatment of insomnia comorbid with cancer: a randomized, partially blinded,
noninferiority trial. J Clin Oncol. 2014;32(5):449-457.
Stress, Sleep, and Inflammation
69
187. Gross CR, Kreitzer MJ, Reilly-Spong M, et al. Mindfulness-based stress reduction
versus pharmacotherapy for chronic primary insomnia: a randomized controlled
clinical trial. Explore (NY). 2011;7(2):76-87.
188. Schmidt S, Grossman P, Schwarzer B, Jena S, Naumann J, Walach H. Treating
fibromyalgia with mindfulness-based stress reduction: results from a 3-armed
randomized controlled trial. Pain. 2011;152(2):361-369.
189. van der Zwan JE, de Vente W, Huizink AC, Bogels SM, de Bruin EI. Physical
activity, mindfulness meditation, or heart rate variability biofeedback for stress
reduction: a randomized controlled trial. Appl Psychophysiol Biofeedback.
2015;40(4):257-268.
190. Vanhuffel H, Rey M, Lambert I, Da Fonseca D, Bat-Pitault F. [Contribution of
mindfulness meditation in cognitive behavioral therapy for insomnia]. Encephale.
2018;44(2):134-140.
191. Wong SY, Zhang DX, Li CC, et al. Comparing the Effects of Mindfulness-Based
Cognitive Therapy and Sleep Psycho-Education with Exercise on Chronic Insomnia:
A Randomised Controlled Trial. Psychother Psychosom. 2017;86(4):241-253.
192. Black DS, O'Reilly GA, Olmstead R, Breen EC, Irwin MR. Mindfulness meditation
and improvement in sleep quality and daytime impairment among older adults with
sleep disturbances: a randomized clinical trial. JAMA Intern Med. 2015;175(4):494-
501.
193. Dykens EM, Fisher MH, Taylor JL, Lambert W, Miodrag N. Reducing distress in
mothers of children with autism and other disabilities: a randomized trial. Pediatrics.
2014;134(2):e454-463.
194. Gross CR, Kreitzer MJ, Thomas W, et al. Mindfulness-based stress reduction for solid
organ transplant recipients: a randomized controlled trial. Altern Ther Health Med.
2010;16(5):30-38.
195. Hoge EA, Bui E, Marques L, et al. Randomized controlled trial of mindfulness
meditation for generalized anxiety disorder: effects on anxiety and stress reactivity. J
Clin Psychiatry. 2013;74(8):786-792.
196. Johns SA, Brown LF, Beck-Coon K, et al. Randomized controlled pilot trial of
mindfulness-based stress reduction compared to psychoeducational support for
persistently fatigued breast and colorectal cancer survivors. Support Care Cancer.
2016;24(10):4085-4096.
197. Malarkey WB, Jarjoura D, Klatt M. Workplace based mindfulness practice and
inflammation: a randomized trial. Brain Behav Immun. 2013;27(1):145-154.
Heather L Rusch
70
198. Nakamura Y, Lipschitz DL, Landward R, Kuhn R, West G. Two sessions of sleep-
focused mind-body bridging improve self-reported symptoms of sleep and PTSD in
veterans: A pilot randomized controlled trial. J Psychosom Res. 2011;70(4):335-345.
199. Nakamura Y, Lipschitz DL, Kuhn R, Kinney AY, Donaldson GW. Investigating
efficacy of two brief mind-body intervention programs for managing sleep
disturbance in cancer survivors: a pilot randomized controlled trial. J Cancer Surviv.
2013;7(2):165-182.
200. Nakamura Y, Lipschitz DL, Donaldson GW, et al. Investigating Clinical Benefits of a
Novel Sleep-Focused Mind-Body Program on Gulf War Illness Symptoms: A
Randomized Controlled Trial. Psychosom Med. 2017;79(6):706-718.
201. Oken BS, Fonareva I, Haas M, et al. Pilot controlled trial of mindfulness meditation
and education for dementia caregivers. J Altern Complement Med. 2010;16(10):1031-
1038.
202. Van Gordon W, Shonin E, Dunn TJ, Garcia-Campayo J, Griffiths MD. Meditation
awareness training for the treatment of fibromyalgia syndrome: A randomized
controlled trial. Br J Health Psychol. 2017;22(1):186-206.
203. Martin LR, Williams SL, Haskard KB, Dimatteo MR. The challenge of patient
adherence. Ther Clin Risk Manag. 2005;1(3):189-199.
204. Collen JF, Lettieri CJ, Hoffman M. The impact of posttraumatic stress disorder on
CPAP adherence in patients with obstructive sleep apnea. J Clin Sleep Med.
2012;8(6):667-672.
205. Guardado P, Olivera A, Rusch HL, et al. Altered gene expression of the innate
immune, neuroendocrine, and nuclear factor-kappa B (NF-kappaB) systems is
associated with posttraumatic stress disorder in military personnel. J Anxiety Disord.
2016;38:9-20.
206. Fox KC, Nijeboer S, Dixon ML, et al. Is meditation associated with altered brain
structure? A systematic review and meta-analysis of morphometric neuroimaging in
meditation practitioners. Neurosci Biobehav Rev. 2014;43C:48-73.
207. Hasenkamp W, Barsalou LW. Effects of meditation experience on functional
connectivity of distributed brain networks. Front Hum Neurosci. 2012;6:38.
208. Nagendra RP, Maruthai N, Kutty BM. Meditation and its regulatory role on sleep.
Front Neurol. 2012;3:54.
209. Winbush NY, Gross CR, Kreitzer MJ. The effects of mindfulness-based stress
reduction on sleep disturbance: a systematic review. Explore (NY). 2007;3(6):585-
591.
Stress, Sleep, and Inflammation
71
210. Carmody J, Baer RA. How long does a mindfulness-based stress reduction program
need to be? A review of class contact hours and effect sizes for psychological distress.
J Clin Psychol. 2009;65(6):627-638.
211. Davidson RJ, Kaszniak AW. Conceptual and methodological issues in research on
mindfulness and meditation. Am Psychol. 2015;70(7):581-592.
212. Britton WB, Lindahl JR, Cahn BR, Davis JH, Goldman RE. Awakening is not a
metaphor: the effects of Buddhist meditation practices on basic wakefulness. Ann N Y
Acad Sci. 2014;1307:64-81.
213. Thornton LM, Andersen BL, Schuler TA, Carson WE, 3rd. A psychological
intervention reduces inflammatory markers by alleviating depressive symptoms:
secondary analysis of a randomized controlled trial. Psychosom Med. 2009;71(7):715-
724.
214. Benedict C, Blennow K, Zetterberg H, Cedernaes J. Effects of acute sleep loss on
diurnal plasma dynamics of CNS health biomarkers in young men. Neurology.
2020;94(11):e1181-e1189.
215. Nilsonne G, Lekander M, Akerstedt T, Axelsson J, Ingre M. Diurnal Variation of
Circulating Interleukin-6 in Humans: A Meta-Analysis. PLoS One.
2016;11(11):e0165799.
216. Lasselin J, Lekander M, Axelsson J, Karshikoff B. Sex differences in how
inflammation affects behavior: What we can learn from experimental inflammatory
models in humans. Front Neuroendocrinol. 2018;50:91-106.
217. Cho HJ, Eisenberger NI, Olmstead R, Breen EC, Irwin MR. Preexisting mild sleep
disturbance as a vulnerability factor for inflammation-induced depressed mood: a
human experimental study. Transl Psychiatry. 2016;6:e750.
218. Dolsen MR, Crosswell AD, Prather AA. Links Between Stress, Sleep, and
Inflammation: Are there Sex Differences? Curr Psychiatry Rep. 2019;21(2):8.
219. Klein SL, Flanagan KL. Sex differences in immune responses. Nat Rev Immunol.
2016;16(10):626-638.
220. Cohen S, Janicki-Deverts D. Who's stressed? Distributions of psychological stress in
the United States in probability samples from 1983, 2006, and 2009. J Appl Soc
Psychol. 2012;42(6):1320–1334.
221. Gilmartin H, Goyal A, Hamati MC, Mann J, Saint S, Chopra V. Brief Mindfulness
Practices for Healthcare Providers – A Systematic Literature Review. The
American Journal of Medicine. 2017;130(10):1219.e1211-1219.e1217.
Heather L Rusch
72
222. Khoury B, Sharma M, Rush SE, Fournier C. Mindfulness-based stress reduction for
healthy individuals: A meta-analysis. J Psychosom Res. 2015;78(6):519-528.
223. Zeidan F, Johnson SK, Gordon NS, Goolkasian P. Effects of Brief and Sham
Mindfulness Meditation on Mood and Cardiovascular Variables. The Journal of
Alternative and Complementary Medicine. 2010;16(8):867-873.
224. MacCoon DG, Imel ZE, Rosenkranz MA, et al. The validation of an active control
intervention for Mindfulness Based Stress Reduction (MBSR). Behav Res Ther.
2012;50(1):3-12.
225. Lin J, Li J, Huang B, et al. Exosomes: novel biomarkers for clinical diagnosis.
ScientificWorldJournal. 2015;2015:657086.
226. Germain A. Sleep disturbances as the hallmark of PTSD: where are we now? Am J
Psychiatry. 2013;170(4):372-382.
227. Colvonen PJ, Drummond SPA, Angkaw AC, Norman SB. Piloting cognitive-
behavioral therapy for insomnia integrated with prolonged exposure. Psychol
Trauma. 2019;11(1):107-113.
228. Colvonen PJ, Straus LD, Acheson D, Gehrman P. A Review of the Relationship
Between Emotional Learning and Memory, Sleep, and PTSD. Curr Psychiatry Rep.
2019;21(1):2.
229. Campbell M, Decker KP, Kruk K, Deaver SP. Art Therapy and Cognitive Processing
Therapy for Combat-Related PTSD: A Randomized Controlled Trial. Art Ther (Alex).
2016;33(4):169-177.
230. Dzierzewski JM, Wallace DM, Wohlgemuth WK. Adherence to Continuous Positive
Airway Pressure in Existing Users: Self-Efficacy Enhances the Association between
Continuous Positive Airway Pressure and Adherence. J Clin Sleep Med.
2016;12(2):169-176.
231. Haroon E, Raison CL, Miller AH. Psychoneuroimmunology meets
neuropsychopharmacology: translational implications of the impact of inflammation
on behavior. Neuropsychopharmacology. 2012;37(1):137-162.
232. Lasselin J, Lekander M, Benson S, Schedlowski M, Engler H. Sick for science:
experimental endotoxemia as a translational tool to develop and test new therapies for
inflammation-associated depression. Mol Psychiatry. 2020.
233. Black DS, Cole SW, Irwin MR, et al. Yogic meditation reverses NF-kappaB and IRF-
related transcriptome dynamics in leukocytes of family dementia caregivers in a
randomized controlled trial. Psychoneuroendocrinology. 2013;38(3):348-355.
Stress, Sleep, and Inflammation
73
234. Davidson RJ, Kabat-Zinn J, Schumacher J, et al. Alterations in brain and immune
function produced by mindfulness meditation. Psychosom Med. 2003;65(4):564-570.
235. Ng TKS, Fam J, Feng L, et al. Mindfulness improves inflammatory biomarker levels
in older adults with mild cognitive impairment: a randomized controlled trial. Transl
Psychiatry. 2020;10(1):21.
236. Rosenkranz MA, Davidson RJ, Maccoon DG, Sheridan JF, Kalin NH, Lutz A. A
comparison of mindfulness-based stress reduction and an active control in modulation
of neurogenic inflammation. Brain Behav Immun. 2013;27(1):174-184.
237. Kappelmann N, Lewis G, Dantzer R, Jones PB, Khandaker GM. Antidepressant
activity of anti-cytokine treatment: a systematic review and meta-analysis of clinical
trials of chronic inflammatory conditions. Mol Psychiatry. 2018;23(2):335-343.
238. Pfau ML, Menard C, Russo SJ. Inflammatory Mediators in Mood Disorders:
Therapeutic Opportunities. Annu Rev Pharmacol Toxicol. 2018;58:411-428.
239. Salvagioni DAJ, Melanda FN, Mesas AE, Gonzalez AD, Gabani FL, Andrade SM.
Physical, psychological and occupational consequences of job burnout: A systematic
review of prospective studies. PLoS One. 2017;12(10):e0185781.
240. Rothenberger DA. Physician Burnout and Well-Being: A Systematic Review and
Framework for Action. Dis Colon Rectum. 2017;60(6):567-576.
Heather L Rusch
74
Let yourself be silently drawn by the strange pull of what you really love.
It will not lead you astray.
― Rumi
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9 APPENDIX
