Psychophysiological Responses to a Brief Self-Compassion Exercise in Armed Forces Veterans

Abstract

Armed Forces personnel are exposed to traumatic experiences during their work; therefore, they are at risk of developing emotional difficulties such as post-traumatic stress disorder (PTSD), following traumatic experiences. Despite evidence to suggest that self-compassion is effective in reducing the symptoms of PTSD, and greater levels of self-compassion are associated with enhanced resilience, self-compassion in armed forces personnel and armed forces veterans remains under-researched. As a result, it is not known if therapeutic approaches that use self-compassion interventions are an acceptable and effective treatment for this population. Having previously shown that a one-off self-compassion exercise has temporary beneficial psychophysiological effects in non-clinical participants, we conducted this proof-of concept study to investigate whether this exercise is equally beneficial in veterans who had experienced deployment to a combat zone. Additionally, we examined if brief a self-compassion exercise can temporarily reduce hyperarousal symptoms and increase feelings of social connectedness. The current study also investigated the association between PTSD symptom severity, emotion regulation, and self-compassion in 56 veterans. All participants listened to a loving-kindness meditation for self-compassion (LKM-S) and psychophysiological recordings were taken throughout. Psychophysiological effects were observed including heart-rate (HR), skin conductance (SCL), and heart-rate variability (HRV) to determine associations with PTSD and changes in response associated with the self-compassion induction. PTSD symptom severity, dispositional emotion regulation, and self-compassion were measured, and participants also completed state measures of hyperarousal and social connectedness before and after the LKM-S. The findings partially demonstrated that self-compassion can be elicited in a veteran population but there were considerable individual differences in psychophysiological responses. The findings are discussed in light of existing theories of PTSD and self-compassion and the implications of using self-compassion based psychological approaches with veterans.

Full text

Frontiers in Psychology | www.frontiersin.org 1 January 2022 | Volume 12 | Article 780319
ORIGINAL RESEARCH
published: 18 January 2022
doi: 10.3389/fpsyg.2021.780319
Edited by:
Andrea Poli,
Università degli Studi di Pisa, Italy
Reviewed by:
Chao Liu,
Huaqiao University, China
Seth Davin Norrholm,
Wayne State University, UnitedStates
*Correspondence:
Anke Karl
A.Karl@exeter.ac.uk
Specialty section:
This article was submitted to
Psychology for Clinical Settings,
a section of the journal
Frontiers in Psychology
Received: 20 September 2021
Accepted: 25 November 2021
Published: 18 January 2022
Citation:
Gerdes S, Williams H and
Karl A (2022) Psychophysiological
Responses to a Brief Self-
Compassion Exercise in Armed
Forces Veterans.
Front. Psychol. 12:780319.
doi: 10.3389/fpsyg.2021.780319
Psychophysiological Responses
to a Brief Self-Compassion Exercise
in Armed Forces Veterans
SamanthaGerdes
1,2, HuwWilliams
1 and AnkeKarl
1*
1 Mood Disorder Centre, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom,
2 The Veterans’ Mental Health and Wellbeing Service, Camden and Islington NHS Trust, London, United Kingdom
Armed Forces personnel are exposed to traumatic experiences during their work; therefore,
they are at risk of developing emotional difculties such as post-traumatic stress disorder
(PTSD), following traumatic experiences. Despite evidence to suggest that self-compassion
is effective in reducing the symptoms of PTSD, and greater levels of self-compassion are
associated with enhanced resilience, self-compassion in armed forces personnel and
armed forces veterans remains under-researched. As a result, it is not known if therapeutic
approaches that use self-compassion interventions are an acceptable and effective
treatment for this population. Having previously shown that a one-off self-compassion
exercise has temporary benecial psychophysiological effects in non-clinical participants,
weconducted this proof-of concept study to investigate whether this exercise is equally
benecial in veterans who had experienced deployment to a combat zone. Additionally,
weexamined if brief a self-compassion exercise can temporarily reduce hyperarousal
symptoms and increase feelings of social connectedness. The current study also
investigated the association between PTSD symptom severity, emotion regulation, and
self-compassion in 56 veterans. All participants listened to a loving-kindness meditation
for self-compassion (LKM-S) and psychophysiological recordings were taken throughout.
Psychophysiological effects were observed including heart-rate (HR), skin conductance
(SCL), and heart-rate variability (HRV) to determine associations with PTSD and changes
in response associated with the self-compassion induction. PTSD symptom severity,
dispositional emotion regulation, and self-compassion were measured, and participants
also completed state measures of hyperarousal and social connectedness before and
after the LKM-S. The ndings partially demonstrated that self-compassion can beelicited
in a veteran population but there were considerable individual differences in
psychophysiological responses. The ndings are discussed in light of existing theories of
PTSD and self-compassion and the implications of using self-compassion based
psychological approaches with veterans.
Keywords: self-compassion, veterans, PTSD, hyperarousal, loving-kindness, heart rate variability,
skin conductance

Gerdes et al. Self-Compassion in Armed Forces Veterans
Frontiers in Psychology | www.frontiersin.org 2 January 2022 | Volume 12 | Article 780319
INTRODUCTION
e impact of war-related trauma on soldiers is now well recognized
and exposure to traumatic events while carrying out occupational
duties can put armed forces personnel at an increased risk for
developing PTSD (Dunn etal., 2015). Reports of PTSD prevalence
rates in the armed forces population vary widely (Kok et al.,
2012) with some estimating rates of PTSD in currently serving
armed forces personnel at 4% (Hotopf et al., 2003; Fear et al.,
2010); however, rates rise exponentially when soldiers are exposed
to combat during deployments (11.9–22.5%; Kang et al., 2003)
and PTSD rates increase with greater exposure to enemy contact
and reghts (Hoge et al., 2004).
One particular characteristic of combat-related PTSD is a
pattern of hypervigilance symptomology that is dierent from
those found in civilian populations (Kimble et al., 2013).
Individuals suering from combat-related PTSD report enhanced
physiological reactivity, an overactive startle response and
emotional numbness compared with those who experience
civilian traumatic events (Prescott, 2012). For soldiers in war
zones, hypervigilance is highly adaptive such as the constant
sensory scanning and searching (e.g., listening for footsteps
and weapon sounds or looking for rising dust and shadows;
(Department of the Army, 1984). Due to the constant threat
to life or of serious physical injury endured for long periods
of time, the hypervigilance is reinforced while on deployment
(Kimble et al., 2013). As a result, it can become habitual and
triggered easily, and dicult to eradicate once back in civilian
life. Individuals are on constant “high alert” even when threat
is low (Kimble et al., 2013), thus becoming problematic in
civilian life as it can lead to disruptions in functioning such
as increased aggression and sleep problems (Germain and
Neilsen, 2003; Ta et al., 2007; Conoscenti et al., 2009).
Within the cognitive model of PTSD, elevated levels of
hypervigilance and being in a threatened state maintains PTSD
in combat veterans as it can prevent adaptive changes to the
trauma memories (Ehlers and Clark, 2000). Veterans might hold
a belief that hypervigilance was what enabled them to survive
the traumatic experience and that they therefore cannot give it
up. is could facilitate engagement in maladaptive coping
strategies and safety behaviors such as constantly being on high
alert and on the lookout for danger (Conoscenti et al., 2009).
e drive to avoid feelings of threat further reinforces hypervigilant
behaviors and prevents adaptive processing of the traumatic
events. Individuals with combat-related PTSD, therefore, nd it
more dicult to engage in psychological therapies where exposure
to traumatic memories is at the core (e.g., Ehlers and Clark, 2009).
Hypervigilance and other PTSD symptoms can leave people
feeling detached and estranged from others and having diculties
experiencing positive feelings (American Psychiatric Association,
2013) as well as a feeling of dierence, or “having changed”
since the traumatic event (Demers, 2011). is can lead to
diculties in maintaining relationships (King etal., 2006) resulting
in a lack of social support which can further contribute to a
deterioration in mental health (Freedman et al., 2015). Further,
the eect of the transition to civilian life is that the social support
network experienced during a career with the armed forces is
no longer available; hence, the combat veterans face an imminent
lack of belongingness and social connection that may have been
adaptive during their service (DeVries et al., 2003; Tick, 2005;
Wessely, 2006). e profound benecial eects of social support
(Brewin et al., 2000; Ozer et al., 2003) and perceived social
connectedness for recovery from psychological trauma and reducing
PTSD have been demonstrated (Freedman et al., 2015). For
example, post-deployment social support is negatively associated
with PTSD in combat veterans (Pietrzak et al., 2009). However,
the masculinized culture of the armed forces that promotes
emotional stoicism (Reit, 2009; McAllister et al., 2018; Neilson
et al., 2020) can prevent people from sharing emotional distress,
and this may be further compounded during civilian life where
veterans may feel alone in their experiences (Demers, 2011).
A lack of social support, diculties in social relationships,
or threats to social connection contribute to PTSD severity
(Freedman et al., 2015) and also can activate the same stress
response system as physical threats to survival, i.e., the ght/
ight response, including the sympathetic nervous system (SNS)
and the Hypothalamus-pituitary–adrenal (HPA) axis (Eisenberger
and Cole, 2012). e combination of threats to social
connection and hypervigilance due to fragmented, emotionally
charged trauma memories can contribute to an elevated ght/
ight response and hence mental health problems in veterans
(Southwick et al., 2005). Elevated physiological arousal (Pole,
2007) and an elevated HPA response have been identied in
people with PTSD. is elevated ght/ight state (i.e.,
hyperarousal) and constant activation of threat mode
(i.e., hypervigilance), combined with a lack of social support
may maintain PTSD in combat veterans, as individuals might
be stuck in “current threat” mode (Ehlers and Clark, 2000).
erefore, therapeutic approaches that emphasize reducing
hyperarousal and the stress response as well as building social
connectedness could reduce PTSD symptoms in veterans. e
new concept of self-compassion has shown to be a promising
approach for alleviation of PTSD symptoms in both civilian
and veteran populations (e.g., Lee, 2009; Steen et al., 2021).
Self-compassion can be described as “an intimate awareness
of the suering of oneself and others with the wish to alleviate
it” (Germer and Ne, 2013). Dispositional self-compassion is
negatively related to psychopathology (Barnard and Curry, 2011;
MacBeth and Gumley, 2012) including PTSD and has been
shown to predict recovery from PTSD (ompson and Waltz,
2008; Meyer et al., 2019). Additionally, self-compassion can
be cultivated in therapeutic settings and is therefore gaining
popularity to treat a number of mental health diculties (e.g.,
Germer and Ne, 2013, 2015) including PTSD and shame-
based ashbacks (Lee, 2009; Daneshvar et al., 2020) as well
as other shame-based diculties (Leaviss and Uttley, 2015).
Additionally, studies have shown that self-compassion could
oer a protective process in preventing suicide in veterans, in
times of distress as higher levels of self-compassion are associated
with lower levels of psychopathology and suicidality (Kelley
et al., 2019; Rabon et al., 2019).
Self-compassion could be benecial for the treatment of
PTSD in several ways: rstly, increasing self-compassion can
reduce the “threat” emotion regulation system (Gilbert, 2009a)

Gerdes et al. Self-Compassion in Armed Forces Veterans
Frontiers in Psychology | www.frontiersin.org 3 January 2022 | Volume 12 | Article 780319
that is reected by the excessive hyperarousal previously used
as a survival mechanism and the negative self-appraisals that
prevent adaptive processing and integration of the traumatic
experience into the individual’s autobiographical memory
(Ehlers and Clark, 2000). Both hyperarousal and negative
self-appraisals are associated with activation of the sympathetic
division of the autonomic nervous system as indicated by
increased heart rate (HR) and skin conductance level (SCL;
Pole, 2007) as part of the ght/ight response. In contrast,
facilitating self-compassion secondly activates the “soothing
and contentment” system (Gilbert, 2009a) characterized by
a calm and content positive state and increased parasympathetic
activation (as indicated by increased heart rate variability;
HRV, Kirschner et al., 2019). is allows the individual not
only to activate self-soothing and kindness but also to feel
safe and socially connected (Gilbert, 2010). Increasing feelings
of social connectedness via the activation of compassion
represents the second possible mechanism via which it could
reduce PTSD symptomology in veterans (e.g., Pearlman and
Curtois, 2005; Freedman et al., 2015).
Facilitating self-compassion in a one-o meditation in
civilian populations has been shown to increase perceived
interpersonal connectedness (Hutcherson et al., 2008) and
state secure attachment (Kirschner et al., 2019). However,
the use of self-compassion with veterans with PTSD is in
its infancy, though initial studies have found that self-
compassion is negatively associated with PTSD (Dahm etal.,
2015), that dispositional self-compassion levels are predictive
of PTSD symptom severity (Hiraoka etal., 2015), and self-
compassion is negatively related to maladaptive coping
strategies such as impulsivity in military recruits (Mantzios,
2014). A 12-week course of loving kindness meditation (LKM)
in veterans with PTSD led to an increase in self-compassion
while symptoms of PTSD decreased (Kearney et al., 2013).
Although self-compassion has demonstrated eectiveness for
shame-based diculties in PTSD (Lee, 2009), the mechanisms
via which self-compassion interventions facilitate PTSD
symptom reduction in veterans are not well understood
to date.
It has not previously been studied whether facilitating self-
compassion in veterans can reduce hypervigilance/hyperarousal
as assessed by self-report and physiological measurements. In
healthy individuals, a one-o short-term Loving Kindness
Meditation for the Self (LKM-S) reduced physiological arousal
symptoms; (i.e., reduced HR, SCL) and increased parasympathetic
activation (i.e., increased HRV; Kirschner et al., 2019). In
contrast, Creaser et al. (2021) found that civilian trauma
survivors without PTSD and with subsyndromal and full PTSD
who followed the same LKM-S had a reduction in negative
self-perception and an increase in positive self-perception but
did not show the expected physiological response pattern.
Interestingly, individuals in the subsyndromal PTSD group who
presented with higher levels of hyperarousal, showed a distinct
physiological and brain response pattern, which indicated a
threat response when instructed to direct compassion to the
self. Similarly, in individuals with a history of recurrent
depression, Kirschner et al. (2021) found that the LKM-S
increased positive self-perception but this was not accompanied
by the expected physiological response pattern. However, aer
completing an 8-week MBCT course, patients with recurrent
depression showed a physiological pattern of calm and content
positive aect (reduced HR and SCL and increased HRV;
Kirschner et al., 2021).
In veterans, one prior study suggests that LKM can reduce
PTSD symptoms (e.g., (Kearney et al., 2013) although to
our knowledge there have been no further empirical studies
to support this. e aim of the current study is to investigate
the eects of a short-term one-o self-compassion meditation
(LKM-S) in veterans who have experienced deployment to
a combat zone. e pre-post changes on self-report hyperarousal
symptoms (DSM-5, PTSD Cluster E) and feelings of social
connectedness were examined. Additionally, we investigated
physiological reactions during the self-compassion meditation
to better understand the eects of the meditation on the
ght/ight response. Specically, we hypothesized that self-
compassion would be cultivated in veterans, in both those
who did and did not have PTSD as indicated by an increase
on the self-compassion questions (Hypothesis 1). Additionally,
we predicted that following the LKM-S there would be a
decrease in self-reported hyperarousal symptoms (Hypothesis
2a) and a reduction in HR and SCL as measures of physiological
arousal (Hypothesis 2b). We further predicted that there
would be an increase in self-reported social connectedness
(Hypothesis 3a) and an increase in HRV as a measure of
parasympathetic activation (Hypothesis 3b). Given that more
severe PTSD presentations can take longer to respond to
psychological interventions (Hogberg et al., 2008), we also
predicted that PTSD severity and emotion suppression would
be negatively associated with the increase of LKM-S related
self-compassion, social connectedness and HRV (Hypothesis
4a) and with the reduction in state hyperarousal and
physiological arousal as indicated by HR and SCL (Hypothesis
4b). Finally, we predicted that dispositional self-compassion
would result in a reverse association pattern and bepositively
associated with the increase of LKM-S related self-compassion,
social connectedness and HRV (Hypothesis 5a) and with
the reduction in state hyperarousal and physiological arousal
(Hypothesis 5b).
MATERIALS AND METHODS
Research Design
e study used a repeated measures design to test Hypotheses
1, 2a, and 3a, using outcome score at Time 1 (pre-LKM-S)
and Time 2 (post-LKM-S) as dependent variables for self-report
state hyperarousal, social connectedness and self-compassion.
For SCL, HR, and HRV (Hypotheses 2b and 3b) the response
in relation to the baseline (prior to the LKM-S) per minute
over 11 min formed the repeated measures. In addition, a
one-sample design was used to determine signicant change
from the baseline that was set to zero. To investigate the role
of individual dierences (Hypotheses 4 and 5), a correlational
design was applied.

Gerdes et al. Self-Compassion in Armed Forces Veterans
Frontiers in Psychology | www.frontiersin.org 4 January 2022 | Volume 12 | Article 780319
Participants
Fiy-six armed forces veterans (52 males, 4 females) took part
in the study. ey were recruited between November 2017 and
April 2018 through local veteran charities, the UK National Health
Service (NHS) and online via social media platforms. Participants
were eligible if they had experienced deployment to a combat
zone during their career in the armed forces and they experienced
combat or signicant exposure to danger during the deployment.
ey were excluded from the study if they had a severe mental
health problem such as schizophrenia or were acutely suicidal.
Participants were also excluded if they had a prior history of
cardiovascular problems including those that reported having
had heart surgery, heart attacks or being on any cardiovascular
medication. All participants gave written informed consent and
the protocol was approved by the South West – Cornwall and
Plymouth Research Ethics Committee (LREC) and the School
of Psychology Ethics Committee of the University of Exeter.
Target sample size was determined a priori using a power
calculation applying G*Power (Faul et al., 2009). Based on a
medium eect size, it was calculated that 54 participants were
needed to determine signicant pre-to post changes in the
dependent variables for a statistical power of 0.95 and alpha = 0.05.
is sample size was deemed sucient for examining the
secondary correlational hypotheses with three predictors and
an assumed large eect size (f2 = 0.35), however if only a medium
eect size is obtained (e.g., f2 = 0.15) a larger sample size (n = 77),
for a power of 0.80 and alpha = 0.05 would be necessary.
We managed to recruit the target sample for Hypotheses 1–3.
e demographic and clinical information about the nal
sample can be seen in Tab l e  1 . e prevalence of PTSD was
n = 19in the current sample (those who had received a previous
diagnosis from a psychiatrist). Based on scores on the PCL-5,
n = 15 (26.8%) currently met criteria for PTSD, n = 5 (8.9%)
met criteria for Subsyndromal PTSD1 on the PCL-5 and n = 36
(64.3%) did not have PTSD. All apart from one of the participants
had PTSD symptoms as a result of their deployment experiences
to a war zone, n = 18 (34%). One participant had PTSD as a
result of an accident on a training operation during a non-combat
deployment. All participants had been deployed to a combat
zone which included conicts such as the Falkland Islands,
Northern Ireland, Kosovo, Iraq, and Afghanistan. Deployment
length ranged from approximately two months to three years
(including leave periods). ere was an average of M = 4.06
(SD = 2.61; Median and Mode = 3) deployments to combat zones
per participant.
ere were n = 27 (48.2%) participants who had sustained
a physical injury while on deployment. Forty participants
(71.4%) had experienced at least one Traumatic Brain Injury
(TBI) as classied by the work of Williams et al. (2010) (see
Tabl e  2 ).
Measures and Materials
Self-Report Measures
e PTSD Checklist for DSM-5 (PCL-5; Weathers et al., 2013)
consists of 20 items, rated on a ve-point Likert-scale, assessing
the twenty DSM-5 symptoms of Post-Traumatic Stress Disorder.
1
Subsyndromal PTSD is categorized as endorsing one Cluster B symptom
(intrusion symptoms), and one of either cluster C (avoidance), D (negative
alterations in cognitions), or E (hyperarousal).
TABLE1 | Demographic information for participants.
Characteristic N = 56
Gender, no. %
Female 4 (7.1)
Male 52 (92.9)
Age 52.1 (12.90)
Marital Status, no. %
Married 38 (67.9)
Single 5 (8.9)
Divorced/separated 5 (8.9)
Cohabiting 4 (7.1)
Engaged 4 (7.1)
Religion, no. %
No religion 22 (39.3)
Church of England 24 (42.9)
Catholic 3 (5.4)
Buddhist 2 (3.6)
Methodist 1 (1.8)
Other 2 (3.6)
Not stated 2 (3.6)
Occupation, no. %
Employed FT 27 (48.2)
Employed PT 13 (23.2)
Retired 15 (26.8)
Unemployed 1 (1.8)
Nationality, no. %
British 54 (96.4%)
Dual British Nationality 2 (3.6%)
Armed Forces Branch, no. %
Army 13 (23.2%)
Royal Navy 6 (10.7%)
Royal Marines 28 (50.0%)
Royal Air Force 6 (11.0%)
Army Reserves 1 (1.8%)
Royal Marines Reserves 1 (1.8%)
Special Forces 1 (1.8%)
Rank at discharge, no. %
Colonel 1 (1.8)
Lieutenant-Colonel 4 (7.1)
Major/Lieutenant Commander 6 (10.7)
Captain/Flight Lieutenant 7 (12.5)
Sub-Lieutenant 1 (1.8)
Sergeant Major 1 (1.8)
Warrant Ofcer 1st Class 4 (7.1)
Warrant Ofcer 2nd Class 1 (1.8)
Sergeant 9 (16.1)
Corporal/Leading Hand 9 (16.1)
Lance Corporal/Junior technician 5 (8.9)
Private/Marine/Senior Aircraftman 7 (12.5)
Physical injury on deployment, no. %
Yes 27 (48.2)
No 29 (51.8)
PTSD from combat experiences, no. %
Yes 18 (32.1)
No 38 (67.9)

Gerdes et al. Self-Compassion in Armed Forces Veterans
Frontiers in Psychology | www.frontiersin.org 5 January 2022 | Volume 12 | Article 780319
Validation studies for the PCL-5 show strong internal consistency
(a = 0.94), test–retest reliability (r = 0.82), and convergent (rs = 0.74–
0.85) and discriminant validity (rs = 0.31–0.60; Blevins etal., 2015).
e Patient Health Questionnaire for depression (PHQ-9;
Kroenke etal., 2001) consists of 9 items, rated on a four-point
Likert-scale, which is used to establish levels of depression in
primary care and other medical settings. e PHQ-9 has
excellent reliability, internal = 0.89 and test re-test = 0.84 validity
for detecting depression = 0.95 (Solomon et al., 2000).
e Emotion Regulation Questionnaire (ERQ, Gross and
John, 2003) consists of 10 items, rated on a seven-point Likert-
scale, assessing the ability to regulate emotions in terms of
cognitive reappraisal2 and expressive suppression.3 Prior research
has shown that the ERQ has high internal reliability, and
convergent and discriminant validity (Gross and John, 2003).
The Self-Compassion Scale-Short Form (SCS-SF; Raes
et al., 2011), consists of 12 items rated on a five-point
Likert-scale assessing trait level of self-compassion. The short
form is near perfectly correlated with the Self Compassion
Scale (SCS) r = 0.98 (Raes et al., 2011) and the scale has
demonstrated validity and reliability (Neff, 2003a).
Visual Analogue scales (ranging from 0 to 100) were
used to establish state levels of self-compassion, hyperarousal
and social connectedness before and after the LKM-S. State
self-compassion was used as a manipulation check to determine
self-compassion induction in participants and also engagement
with the meditation. The VAS measure is adapted from
Kirschner et al. (2019) and questions are taken from the
Self-Compassion Scale (SCS; Neff, 2003a), social connectedness
questions are based on the state adult attachment measure
(SAAM; Gillath et al., 2009) and four adapted items from
the PCL-5 have been added to measure state hyperarousal.
The VAS has been used in previous studies (Kirschner etal.,
2019, 2021) which found Cronbach’s α = 0.66 for state affiliative
affect, state self-compassion (Cronbach’s α = 0.73 in this
sample) and state self-criticism (Cronbach’s alpha in this
sample was 0.73 for the inadequate self, 0.76 for the hated
self, and 0.77 for reassure self).
2
Cognitive Reappraisal is cognitive change which can alter how we interpret
a situation and therefore changes the emotional response (Lazarus and
Alfert, 1964).
3
Expressive Suppression is the ability to inhibit the emotive-expressive behavior
triggered by an emotional response (Gross, 1998).
Loving Kindness Meditation
A self-compassion meditation (LKM-S) was used to induce
self-compassion in the current study. The LKM-S has been
developed by the ACCEPT clinic, at the University of
Exeter Mood Disorder Centre. The LKM-S audio clip was
recorded by an experienced mindfulness practitioner, and
the LKM-S has been used in prior research (e.g., Kirschner
et al., 2019). Participants are asked to direct loving/friendly
feelings toward themselves and others and the audio clip
is 11.5 min in length.
Physiological Measurements
All physiological parameters were recorded continuously using
a BIOPAC MP150 system using the AcqKnowledge 4.2 (BIOPAC
Systems; Goleta, CA) soware. HR and HRV was determined
from the electrocardiogram (ECG) using standard procedures
(Berntson et al., 1997; Berntson and Stowell, 1998). ECG was
recorded from below the participant’s right collar bone and
the participant’s le lower ribcage using a BIOPAC ECG100C
amplier at a sampling rate of 1 kHz with a low pass lter
of 0.5 Hz and a high pass lter of 35 Hz. Skin conductance
levels (SCL) were recorded using a BIOPAC SCL100C amplier
and a skin resistant transducer (TSD203) from the middle
phalanx of the rst and second ngers of the participant’s
non-dominant hand, at a sampling rate of 500 Hz with a low
pass lter of 1.0 Hz. SCL was pre-processed using recommended
procedures (Lykken et al., 1966).
Procedure
Participants were self-selected and were recruited from a range
of veteran organizations and charities in the South West of
England, NHS services in Devon and online social media
adverts. Ninety-two people expressed an interest in the study
and 81 people completed the telephone screening. Seventy
participants were eligible and signed up to take part in the
study, 14 participants dropped out at this stage due to reasons
such as work commitments and illness. A total of 56 participants
completed the study. Eligible participants were booked in for
a testing session at the University of Exeter following a telephone
screening call. e study procedure, which lasted approximately
1–1.5 h, included collecting demographic information, completing
psychometric measures, and listening to the compassion
meditation (LKM-S) while physiological recordings were taken.
Standardized instructions were given for the VAS questions
and LKM-S audio. e participants listened to the LKM-S in
a quiet room in the psychophysiological laboratory at the
University of Exeter. Instructions were given to the participants
and they were given the opportunity to ask questions, before
the researcher le the room and the participant listened to
the LKM-S audio. All participants received a reimbursement
for their time of £10.
Data Analysis
ere was missing psychophysiological data for one participant
therefore the analysis for physiological data is based on 55
participants. No other missing data were detected in the data
TABLE2 | Traumatic Brain Injury Assessment (Williams etal., 2010).
Classication N = 56 (%)
0 = No history 15 (26.8)
1 = Feeling dazed and confused but no LOC, minor concussion 1 (1.8)
2 = LOC < 10 min, mild TBI 24 (42.9)
2a = LOC but no concussion symptoms 14 (25.0)
3 = LOC 10 to 30 min, complicated mild TBI 1 (1.8)
4 = LOC 30 to 60 min, moderate/severe TBI 1 (1.8)
5 = LOC > 60 min, very severe TBI 0
LOC = Loss of consciousness. TBI was assessed over the participant’s lifetime rather
than restricted to just their armed forces career.

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set. Outliers were detected aer examining boxplots, however
inspection of their values did not reveal them to be extreme,
so they were kept in the analysis in order to include all
participants in the analysis. e outlying data points were
changed to the next closest value that was under the cut o,
which is a technique for dealing with outliers, while maintaining
the shape of the sample distribution but the outliers do not
distort the data (Tabachnick and Fidell, 2007). Assumptions
of normality were not violated. For the regression analysis,
assumptions of independence of observations, linearity,
homoscedasticity, normality, and multicollinearity were
all fullled.
Data pre-processing and further statistical analyses of the
psychophysiological data followed established procedures; i.e.,
determining the size of the response in relation to a
pre-induction baseline as per previous studies (Kirschner
etal., 2019). To test Hypotheses 1a, 2a, and 3a, paired sample
t-tests were used to examine pre and post scores. Repeated
measures ANOVAs over the 11 timepoints were conducted
to investigate if there is a signicant main eect of time.
One sample t-tests were used for the psychophysiological
data to determine whether scores diered from zero (i.e.,
HRV; as index of parasympathetic activation and HR, SCL
as measure of sympathetic arousal; Hypotheses 2b and 3b).
Correlations and regression analysis were used to examine
the associations between responses to the LKM-S and individual
dierences in PTSD severity, emotion regulation, and
dispositional self-compassion (Hypotheses 4 and 5). For this,
residualized gains scores (RGS; Mintz etal., 1979; Williams
et al., 1984) were calculated for state hyperarousal, self-
compassion, and social connectedness, which were used as
outcome variables.
RESULTS
Change in State Self-Compassion
(Hypothesis 1)
In line with Hypothesis 1, there was a signicant increase in
state self-compassion from pre to post LKM-S, F (1, 55) = 13.62,
p = 0.001, ηp2 = 0.199 (Figure 1).
Change in State Hyperarousal
(Hypothesis 2a)
In line with our hypothesis, there was a signicant reduction
in state arousal pre to post the LKM-S, F (1, 55) = 17.59,
p < 0.001, ηp2 = 0.242 (Figure 2).
Physiological Arousal Response
(Hypothesis 2b)
Heart Rate Response
Overall, there was a signicant eect of time on HR response,
F (10, 45) = 3.57, p = 0.002, ηp2 = 0.442 (Figure 3) suggesting a
rise of HR toward the end of the LKM-S. Although the one-sample
t-test revealed that mean HR response (M = 0.52, SD = 2.71) did
not signicantly dier from zero, t(54) = 1.68, p = 0.09, Cohen’s
d = 0.27, it is of interest that, the one-sample t-test revealed that
HR response to directing compassion towards the self (6–11 min;
M = 0.87, SD = 3.36) revealed a signicantly increased HR,
t(54) = 2.01, p = 0.04, Cohen’s d = 0.27. is indicates that a one-o
LKM-S did not signicantly reduce physiological arousal as indicated
by HR, on the contrary, there is indication of an increase in
physiological arousal when individuals direct compassion
toward themselves.
Skin Conductance Level Response
Overall, there was a signicant eect of time, F(10, 45) = 6.00,
p < 0.001, ηp2 = 0.571 (Figure4) suggesting a reduction of SCL.
A one-sample t-test revealed that the mean SCL response
(M = −0.04, SD = 0.07) was signicantly lower than zero,
t(54) = −4.33, p < 0.001, C ohen’s d = −0.58. is indicates that
there was a reduction in sympathetic arousal as indicated by
FIGURE1 | Change in state self-compassion (pre to post).
FIGURE2 | Change in state hyperarousal (pre to post).

Gerdes et al. Self-Compassion in Armed Forces Veterans
Frontiers in Psychology | www.frontiersin.org 7 January 2022 | Volume 12 | Article 780319
SCL, during the one-o LKM-S, and a medium eect size
was observed.
Change in Social Connectedness
(Hypothesis 3a)
Contrary to our hypothesis, there was no signicant increase
in social connectedness from pre to post the LKM-S, F
(1, 55) = 2.36, p = 0.130, ηp2 = 0.041 (Figure 5).
Parasympathetic Response
(Hypothesis 3b)
Heart Rate Variability Response
ere was a signicant eect of time, F (10, 45) = 2.57, p = 0.015,
ηp2 = 0.364 (Figure 6). A one-sample t-test revealed that mean
HRV response (M = −0.05, SD = 1.06) did not signicantly dier
from zero, t(54) = −0.61, p = 0.54, Cohen’s d = −0.08. is indicates
that a one-o LKM-S did not signicantly increase
parasympathetic activation as indicated by HRV.
Role of Individual Differences (Hypotheses
4 and 5)
Effects of Individual Differences on Change in
Self-Compassion
A multiple regression was used to predict the change in
self-compassion, as measured by the VAS, pre–post the loving
kindness meditation (LKM-S). Overall, the regression model
was signicant, F(1,53) = 4.08, p = 0.048; R2 = 0.07, and explained
7% of variance. Overall, levels of state self-compassion at
both pre and post time points were associated with PTSD
(r = −0.496, p < 0.001), trait self-compassion (r = 0.498, p < 0.001)
and emotion suppression (r = −0.296, p = 0.027). However,
PTSD severity, trait self-compassion, and emotion suppression
were not signicantly associated with LKM-S-induced state
self-compassion change. Instead, the greater increase in state
self-compassion was associated with reduced skin conductance
to compassion for others (rst 5 min of the LKM-S), β = −0.267,
t = −2.02, p = 0.048.
FIGURE3 | Heart rate (HR) response over time.
FIGURE4 | Skin conductance (SCL) response over time.
FIGURE5 | Change in social connectedness (pre to post).
FIGURE6 | HR variability over time.

Gerdes et al. Self-Compassion in Armed Forces Veterans
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Effects of Individual Differences on Change in
Social Connectedness
A multiple regression was used to predict the change in social
connectedness pre to post the LKM-S. Overall, the regression
model was signicant, F(1,53) = 4.26, p = 0.044; R2 = 0.07, and
explained 7% of variance. ough the levels of social
connectedness at both time points were negatively associated
with PTSD (r = −0.649, p < 0.001), self-compassion (r = 0.594,
p < 0.001) and emotion suppression (r = −0.433, p = 0.001), PTSD
severity, trait self-compassion, and emotion suppression were
not signicantly associated with LKM-S-induced change in social
connectedness. Instead, greater increase in social connectedness
associated with higher baseline HRV, β = 0.273, t = 2.06, p = 0.044.
Effects of Individual Differences on Change in
State-Hyperarousal
A multiple regression was used to predict the change in state-
hyperarousal, as measured by the VAS, pre–post the loving
kindness meditation (LKM-S). Overall the regression model
was signicant, F(2,52) = 9.22, p < 0.001; R2 = 0.26, and explained
26% of variance. Although state arousal at both time points
was associated with PTSD (r = 0.768, p < 0.001), self-compassion
(r = −0.453, p < 0.001) and emotion suppression (r = 0.318,
p = 0.017), PTSD severity, trait self-compassion and emotion
suppression were not signicantly associated with LKM-S-
induced arousal change. Instead, greater state arousal reduction
was associated with state change in social connectedness,
β = −0.403, t = −3.37, p = 0.001, and baseline heart rate, β = 0.347,
t = 2.90, p = 0.005.
Effects of Individual Differences on Heart Rate
Response
A regression model was used to predict HR response in compassion
to others, which was signicant: F(1,53) = 4.51, p = 0.038; R2 = 0.08
(8% of variance explained). However, only emotion suppression
was signicantly associated with change in HR when directing
compassion to others, β = 0.280, t = 2.12, p = 0.038.
Effects of Individual Differences on Skin
Conductance Level Response
PTSD severity, trait self-compassion, and emotion suppression
were not signicantly associated with LKM-S-induced SCL response.
Effects of Individual Differences on Heart Rate
Variability Response
A regression model was used to predict the HRV response when
directing compassion to the self, which was signicant, F(1,53) = 5.54,
p = 0.022; R2 = 0.10, and explained 10% of variance. However only
trait self-compassion was signicantly associated with change in
HRV when directing compassion to self, β = 0.308, t = 2.35, p = 0.022.
Exploratory Analyses: Traumatic Brain
Injury
No signicant associations were found between TBI severity
and any of the variables.
DISCUSSION
is study aimed to investigate the eects of a brief, one-o
loving kindness meditation for the self (LKM-S) on state self-
compassion, hyperarousal, social connectedness, and physiological
responses, in armed forces veterans who had experienced
deployment to a combat zone. Following one’s listening to the
LKM-S, participants had a signicant increase in state self-
compassion and a signicant reduction in self-reported
hyperarousal. Additionally, there was a decrease in the SCL
response following the LKM-S. However, there was no increase
in state social connectedness and there was not the expected
increase in HRV and decrease in HR. Interestingly, the
physiological responses were partially associated with individual
dierences in trait self-compassion and emotion regulation but
not with PTSD severity as we predicted.
Overall, the ndings are partially in line with previous
research by Kearney etal. (2013) who found that veterans who
took part in a 1.5 h weekly loving-kindness meditation course
over 12 weeks, had increased levels of state self-compassion
and reduced PTSD symptoms, including levels of state arousal,
immediately aer the treatment and at a 3-month follow-up.
Additionally, changes in self-compassion mediated the changes
in PTSD symptoms pre to post treatment. However, in the
current study the changes in the physiological responses were
not in line with our predictions except for SCL. We had
hypothesized this in line with previous ndings from Kirschner
et al. (2019) who found that the LKM-S induced a pattern of
reduced physiological arousal (HR and SCL reductions) and
increased parasympathetic activity (HRV increase).
ere are several possible explanations for the physiological
ndings of this study. First, there could be a “dose–response”
eect, whereby a one-o administration of a short (11.5 min)
LKM-S is not enough to have an impact at a physiological level
in a clinical sample. In line with PTSD theories (Ehlers and
Clark, 2000) and the tripartite model of emotion regulation
(Gilbert, 2009a), it may bemore challenging for trauma survivors,
in particular those with higher PTSD symptoms, to switch from
“threat and self-protection” system to the “soothing and
contentment” emotion system. In contrast to the ndings of the
current study, a longer loving-kindness meditation course (Kearney
etal., 2013) where veterans attended weekly sessions over 12-weeks,
led to signicant reductions in PTSD symptoms and also an
increase in self-compassion. Additionally, the course was run by
experienced mindfulness teachers who guided participants through
loving-kindness meditations and also encouraged discussion around
integrating loving-kindness meditation into everyday life.
Participants were also provided with a book and CD to encourage
practice between the weekly sessions. Comparing our and Kearney’s
ndings suggests that a longer and more in-depth loving-kindness
meditation practice may be needed to establish changes on a
physiological level in individuals with an overactivated threat
system such as those with PTSD.
Second, and in support of the notion that an overactivated
threat system may aect a person’s ability to engage eectively
with a one-o LKM-S, the absence of the expected physiological
eect is more in line with previous research in a sample of

Gerdes et al. Self-Compassion in Armed Forces Veterans
Frontiers in Psychology | www.frontiersin.org 9 January 2022 | Volume 12 | Article 780319
individuals with a history of recurrent depression, some of
which had reported early childhood adversity (Kirschner etal.,
2021). Prior to an 8-week course of mindfulness-based cognitive
therapy (MBCT), the participants did not have a reduction
in physiological arousal and an increase in parasympathetic
activation aer listening to the LKM-S, despite self-reported
increases in state self-compassion, which is similar to our
ndings in a veteran population. On the contrary, participants
in the current study showed an increase in physiological arousal
through an elevated heart-rate, and in Kirschner et al. (2021)
showed an indication of increased arousal and reduced HRV,
when directing compassion to themselves, thus supporting the
theoretical accounts cited above (Ehlers and Clark, 2000; Gilbert,
2009a). Interestingly, the group of recurrent depressed individuals
in Kirschner et al. (2021) who completed the MBCT, which
has been shown to increase dispositional self-compassion despite
not having a direct compassion component (Kuyken et al.,
2010), showed the predicted reduction in HR and SCL and
increase in HRV post intervention, whereas the untreated
control group showed a more elevated SCL response at the
second exposure to the LKM-S. Taken together, our and the
previous studies (Kirschner, 2021) suggest that a “one-o”
self-compassion meditation in individuals with an overactivated
threat system may result in a subjective eect for participants
as recorded by self-report measures, but does not on an
automatic, habitual level, which would have been reected in
participants’ physiological responses.
In contrast to our hypothesis, we also did not nd that
the one-o LKM-S increased a feeling of social connectedness
as had been previously reported by Hutcherson et al. (2008)
in civilian populations. Given that self-compassion approaches
activate the “soothing and contentment” system, which is
underpinned by the parasympathetic nervous system and enables
feelings of social safety and connectedness (e.g., Gilbert, 2010),
wehypothesized that participants would experience an increase
in feelings of social connectedness aer listening to the LKM-S.
It might be that similarly to physiological responses, there is
a “dose–response” eect, and participants need longer than a
short meditation to experience changes in their felt experience
of social connectedness. In addition, this may be due to an
inherent lack of social support given that veterans have oen
needed to adapt to a dierent social system in civilian life
aer leaving the armed forces. is can mean that veterans
are without the social networks and social support that were
so adaptive during service in the armed forces (Wessely, 2006)
and therefore might explain why we did not see the expected
changes following the LKM-S in the current study.
We hypothesized that PTSD severity and emotion suppression
would benegatively associated with the increase of LKM-S related
self-compassion, social connectedness and HRV (Hypothesis 4a),
given that it is well-established that severity of PTSD aects
participants response to and ability to engage in psychological
interventions (Hogberg et al., 2008). However, we did not nd
support for a role of PTSD symptoms. is was unexpected
but could bedue to the sample largely consisting of participants
not fullling criteria for full or subsyndromal PTSD resulting
in overall low levels of PTSD severity in our participants. Instead,
wefound that there was partial support for role of dispositional
self-compassion and emotion suppression. ose with lower levels
of self-compassion and those who use strategies such as emotion
suppression, found it more dicult to engage with the LKM-S
exercise, which is in line with the work by Gilbert (2010) around
fears and blocks to compassion in those with low levels of
dispositional self-compassion, i.e., people who have low levels
of self-compassion can nd it threatening to engage in compassion
which is seen in an elevated threat response (Gilbert, 2010).
Oen, this is due to having experienced past trauma and especially
those who have experienced interpersonal trauma, such as that
in combat, are particularly susceptible to this aversive response.
In addition, people who use emotion suppression as a strategy
to manage emotions, nd it more dicult to engage with and
experience positive emotional states when they arise, such as
social safety and connectedness associated with the “soothing
and contentment” system (Gilbert, 2010). Although suppressing
emotions can be adaptive for soldiers in combat situations and
is likely to be reinforced as a habitual response (Neilson et al.,
2020), it can cause problems once veterans are re-immersed in
civilian life as it is dicult to establish social safety and feel
connected to others (e.g., Prescott, 2012). Similarly to altering
physiological responses, it is more dicult to change emotion
suppression in veterans when it has been conditioned as part
of their occupational role combat trauma (Prescott, 2012). Given
the high percentage of mild traumatic brain injury (mTBI) in
our sample, which could aect emotion regulation abilities and
contribute to posttraumatic stress symptoms (Belanger et al.,
2009; Mounce etal., 2013), weadditionally explored the associations
of mTBIs and response to LKM-S and our symptom and
dispositional measures. No signicant associations were revealed,
which suggests that mTBIs were not associated with individuals’
ability to engage in a one-o self-compassion meditation.
LIMITATIONS
Overall, the interpretation of the ndings of the current study
needs to take into account several limitations.
Firstly, there was not a control group of participants who
were not exposed to the LKM-S. is means we were not
able to determine whether the changes noted were due to
other factors, such as becoming more comfortable in the
surroundings. It would have been interesting to determine
whether there were baseline dierences in physiological responses
in veterans who have experienced deployment to a combat
zone vs. a civilian group of trauma survivors who have not
held a role in the armed forces, as studies have shown that
combat trauma results in higher levels of hyperarousal than
does other types of trauma (Prescott, 2012). Additionally, there
was no follow up aer the study, so we are not aware for
how long the changes in self-compassion were maintained.
e VAS scale was used in the study as a self-report measure,
and it is not known whether individual dierences in emotional
expression and motor control aected the responses across
participants. In terms of the sample, there was an unequal
proportion of men and women in the study, which is a common

Gerdes et al. Self-Compassion in Armed Forces Veterans
Frontiers in Psychology | www.frontiersin.org 10 January 2022 | Volume 12 | Article 780319
recruitment bias in veteran populations and is representative
of the armed forces population. ere was also a large dierence
in the severity of PTSD in participants – some had no symptoms
at all, whereas others had very severe levels of PTSD. Additionally,
the measurement of PTSD in the current study relied on self-
report measures rather than clinician-administered interviews,
so it might be that some participants felt unable to disclose
their distress in the study setting. Another limitation of the
sample is that although the screening process excluded
participants who had not experienced combat or exposure to
life threatening danger during their deployment to combat
zones, the length of and number of deployments was not
controlled for. Lastly, although the target sample size for the
current study was calculated a priori, the sample size recruited
meant that for the regression analyses, we were only able to
detect medium-to-large eect sizes.
CONCLUSION
Overall, the results demonstrate that there are temporary benets
of a one-o compassion meditation on self-report measures of
self-compassion and hyperarousal but not on physiological responses.
Our results suggest that a self-compassion-based approach appeared
acceptable for veterans who are experiencing emotional distress
including PTSD. Ours and previous ndings considered together
(Kearney etal., 2013; Kirschner etal., 2021) suggest that compassion-
based approaches are potentially benecial for clinical samples
and could extend or complement existing psychological treatments
for veterans with PTSD, given the well-established role of social
support for recovery from trauma and PTSD, (Brewin etal., 2000;
Ozer et al., 2003). e ndings also highlight the importance of
individual dierences and the need for a longer-term intervention
in such populations. Given the need for treatments for PTSD to
create lasting changes that are on a psychological as well as
physiological level, increasing HRV could bean important treatment
target for development of better self-soothing/emotion regulation
in trauma survivors (e.g., Arch etal., 2013). Additionally, reducing
hyperarousal and increasing social connectedness are areas that
can be targeted in treatment for PTSD.
FUTURE RESEARCH
Future studies should investigate the individual dierence factors
identied in the current study, such as the eect on the
participant’s ability to engage with self-compassion approaches,
including cultivating feelings of compassion toward oneself and
others (e.g., Gilbert, 2010). For example, Creaser et al. (2021)
found that people who had high levels of PTSD hyperarousal
symptoms (also common in veterans) had a large threat response
as indicated by physiological measures, when instructed to
direct compassion toward oneself. Gaining further understanding
of the eects of individual dierences on ability to engage
with self-compassion, could be key in understanding why
psychological therapies for combat trauma are less eective
compared with other types of trauma (Bradley et al., 2005);
therefore, it is important that researchers continue to develop
an understanding in this area. Additionally, it might be that
there are dierent PTSD symptom patterns and a link between
numbing/emotion suppression and threat response indicators,
such as HR (Gutner et al., 2010), which also warrant further
investigation. Activating self-compassion in veterans could
provide a helpful avenue to address the issues of shame and
moral injury (Litz etal., 2009; Saraiya and Lopex-Castor, 2016)
that also appear to maintain hyperarousal symptoms in PTSD
(Feiring and Taska, 2005) and can lead to social withdrawal
and lack of social connectedness (Litz et al., 2009).
DATA AVAILABILITY STATEMENT
e raw data cannot be shared because the participants did
not agree that their data can be shared at the consent stage.
Requests to access the datasets should be directed to Anke
Karl at A.Karl@exeter.ac.uk.
ETHICS STATEMENT
e studies involving human participants were reviewed and
approved by the South West – Cornwall and Plymouth Research
Ethics Committee (LREC) and the School of Psychology Ethics
Committee of the University of Exeter. e patients/participants
provided their written informed consent to participate in this study.
AUTHOR CONTRIBUTIONS
SG, HW, and AK contributed to the conception and design
of the study. SG and AK organized the database and performed
the statistical analysis. SG wrote the rst dra of the manuscript.
AK wrote sections of the manuscript. All authors contributed
to the article and approved the submitted version.
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