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Relationships between mindfulness practice and levels
of mindfulness, medical and psychological symptoms
and well-being in a mindfulness-based stress reduction program
James Carmody Æ Ruth A. Baer
Accepted: August 17, 2007 / Published online: 25 September 2007
! Springer Science+Business Media, LLC 2007
Abstract Relationships were investigated between home
practice of mindfulness meditation exercises and levels of
mindfulness, medical and psychological symptoms, per-
ceived stress, and psychological well-being in a sample of
174 adults in a clinical Mindfulness-Based Stress Reduc-
tion (MBSR) program. This is an 8- session group program
for individuals dealing with stress-related problems, illness,
anxiety, and chronic pain. Participants completed measures
of mindfulness, perceived stress, symptoms, and well-
being at pre- and post-MBSR, and monitored their home
practice time throughout the intervention. Results showed
increases in mindfulness and well-being, and decreases in
stress and symptoms, from pre- to post-MBSR. Time spent
engaging in home practice of formal meditation exercises
(body scan, yoga, sitting meditation) was significantly
related to extent of improvement in most facets of mind-
fulness and several measures of symptoms and well-being.
Increases in mindfulness were found to mediate the rela-
tionships between formal mindfulness practice and
improvements in psychological functi oning, suggesting
that the practice of mindfulness meditation leads to
increases in mindfulness, which in turn leads to symptom
reduction and improved well-being
Keywords Mindfulness ! Mindfulness based stress
reduction ! Meditation ! Medical symptoms ! Psychological
symptoms ! Wellbeing ! Stress
An increasing body of research supports physical and
mental health benefits of participation in mindfulness
training. Recent reviews of the empirical literature (Baer
2003; Grossman et al. 2004; Salmon et al. 2004; Hayes
et al. 2006) suggest that several interventions that incor-
porate mindfulness, including mindfulness-based stress
reduction (MBSR) (Kabat-Zinn 1982; Kabat-Zinn 1990),
mindfulness-based cognitive therapy (MBCT) (Segal et al.
2002), dialectical behavior therapy (DBT) (Linehan 1993)
and acceptance and commitment therapy (ACT) (Hayes
et al. 1999); lead to clinically significant improvements in
psychological functioning in a wi de range of populations.
As evidence for the efficacy of these interventions con-
tinues to g row, the importance of investigating the mech-
anisms of action by which mindfulness training exerts
salutogenic effects is increasingly recognized (Dimidjian
and Linehan 2003; Baer et al. 2006; Hayes et al. 2006;
Shapiro et al. 2006). Examination of this question requires
methods to assess levels of mindfulness to determine
whether individuals engaged in the practice of mindfulness
are in fact becoming more mindful over time, and if so,
whether these increases are responsible for the positive
outcomes observed.
The recent literature includes several new ly developed
self-report measures of a gener al tendency to be mindful in
daily life (Baer et al. 2004); (Buchheld et al. 2001; Brown
and Ryan 2003; Feldman et al. In press). These measures
have been shown to be significantly correlated with each
other and to have promising psychometric properties (Baer
et al. 2006). However, differences in their content and
J. Carmody (&)
Division of Preventive and Behavioral Medicine, University
of Massachusetts Medical School, Shaw Building,
Room 214, 55 Lake Ave North, Worcester, MA 01655, USA
e-mail: james.carmody@umassmed.edu
R. A. Baer
Department of Psychology, University of Kentucky, Lexington,
KY, USA
123
J Behav Med (2008) 31:23–33
DOI 10.1007/s10865-007-9130-7
structure suggest some disagreement between researchers
about how mindfulness should be defined and operation-
alized. In particular, the number of components or facets of
mindfulness varies widely across instruments. In a recent
study of facets of mindfulness, Baer et al. (2006) con-
ducted exploratory factor analysis of the combined item
pool from all available mindfulness questionnaires and
found that a five-factor structure appeared to capture sev-
eral distinct but relat ed underlying dimensions. Items with
the highest loadings on each of the five factors (and low
loadings on all other factors) were combined to form the
Five Facet Mindfulness Questionnaire (FFMQ) (Baer et al.
2006), which assesses five elements of mindfulness. These
include observing (attending to or noticing internal and
external stimuli, such as sensations, emotions, cognitions,
sights, sounds, and smells), describing (noting or mentally
labeling these stimuli with words), acting with awareness
(attending to one’s current actions, as opposed to behaving
automatically or absent-mindedly), non-judging of inner
experience (refraining from evaluation of one’s sensations,
cognitions, and emotions) and non-reactivity to inner
experience (allowing thoughts and feelings to come and go,
without attention getting caught up in them). Examples of
items for each factor can be seen in Table 1.
These five facets of mindfulness have shown good
internal consistency and correlations in the expected
directions with many variabl es predicted to be related to
mindfulness, such as experiential avoidance, thought sup-
pression, openness to experience, and emotional intelli-
gence (Baer et al. 2006). Significant relationships with
meditation experience in long-term meditation practitio-
ners also have been documented (Baer et al. 2007), but
changes in these facets of mindfulness over the course of a
mindfulness-based program in a clinical setting have not
been investigated. One purpose of the current study
therefore, was to exam ine whether participation in MBSR
is associated with changes in levels of mindfulness, as
measured by the FFMQ.
The foundation and methodology of MBSR has been
described in detail elsewhere (Kabat-Zinn 1982; Kabat-
Zinn 1990). Briefly, it is a group program that focuses on
the cultivation of mindfulness through instruction in formal
meditation practices (sitting meditation, body scan, mind-
ful yoga), and the integration of this capacity into everyday
life as a coping resource for dealing with intensive physical
symptoms and difficult emotions (Kabat-Zinn 1994). Par-
ticipants attend eight weekly 2 1/2 h sessions, plus an all-
day session on a weekend day during the sixth week. These
sessions include training in formal mindfulness prac tices as
well as group interaction. Class discussion centers around
the challenges and achievements participants are experi-
encing using mindfulness in the face of stressful situations
occurring in their everyday lives. In the body scan, par-
ticipants focus attention sequentially on parts of the body,
non-judgmentally noticing whatever sensations may be
present in each area. Mindful hatha yoga postures also are
practiced to develop awareness during gentle movements
and stretching. In sitting meditation, participants use
awareness of the sensations of breathing as a baseline
attentional focus, while noticing any other sensa tions in the
body, sounds in the environment, and/or cognitions and
feeling states that also present themselves to attention. In
addition, participants are encouraged to engage in informal
mindfulness practice by doing everyday activities (such as
eating, walking, washing the dishes, etc) with full aware-
ness of the associated movements, sensations, cognitions
and feelings that may be present. Participants are give n two
CD’s containing instructions to guide their formal medi-
tation practices (body scan, yoga, and sitting meditation)
and encouraged to practice at home by listening to the CD
for 45 min each day throughout the seven weeks of the
program (Kabat-Zinn 1990).
The importance of regular out-of-class practice in
establishing the capacity for mindfulness in everyday life,
and hence its purported benefits, is also clearly stated in
other mindfulness-based programs. The manual for MBCT
recommends 45 min of daily practice in order to obtain the
benefits of participation (Segal et al. 2002) and a recent
ACT man ual (Hayes and Smith 2005) suggests practicing
for 15–30 min per day. In DBT, the importance of regular
practice is emphasized, but specific practice goals are
determined by clients and their therapists. While this
expectation of daily practice is well established in the
Buddhist meditation traditions upon which these programs
Table 1 Example items for mindfulness facets
Facet Example item
Observing I notice the smells and aromas of things.
Nonreactivity to inner experience I perceive my feelings and emotions without having to react to them.
Describing I’m good at finding words to describe my feelings.
Nonjudging of inner experience I think some of my emotions are bad or inappropriate and I shouldn’t feel them. (R)
Acting with awareness I find myself doing things without paying attention. (R)
Note: R = reverse-scored item (higher scores represent higher levels of mindfulness)
24 J Behav Med (2008) 31:23–33
123
draw, there is limited empirical evidence for the effects of
home practice in clinical populations.
In a sample of women with binge eating disorder who
completed a 6 week mindfulness-based treatment, Kris-
teller and Hallett (1999) found that time spent in the practice
of eat ing-related mindfulness exercises was significantly
correlated with degree of improvement in binge eating.
Practice of ‘‘mini-meditations,’’ in which participants stop
for a few moments at key times during daily activities to
practice nonjudgmental awareness of thoughts and feelings,
was significantly related to improvements in depressive
symptoms. In a subsequent study with a similar popul ation,
time spent engaging in eating-related mindfulness exercises
was significantly related to improvements in eating control
(Kristeller et al. under review). In a study of MBSR with
cancer outpatients, Speca et al. (2000) reported that home
practice of meditation was significantly related to
improvements in mood. In contrast, Astin (1997 ) found that
practice time and symptom improvement were not signifi-
cantly correlated in a sample of college students completing
MBSR. Similarly, Davidson (2003) found no relationship
between reporte d practice time during an MBSR course and
degree of change in either biological or self-report measures
in a worksite sample of healthy employees. Since most
participants in mindfulness-based programs are likely to
have many competing time demands, the disclosure of the
expectation of lengthy out-of-class practice may act as a
barrier to participation for some. For these reasons, and also
to further understanding of mechanisms of action, it is
important to clarify and confirm the role of home practice in
obtaining the program’s potential benefits.
In light of the above, the purpose of the present study
was to investigate three related questions: (1) Whether
participation in MBSR was associated with increases in
mindfulness as measured by the FFMQ; (2) if such
increases were obser ved, whether the amount of out-
of-class practice of mindfulness was related to improve-
ment in mindfulness scores; and (3) if support for this
relationship was found, whether the increases in levels of
mindfulness mediate the relationship between mindfulness
practice and any observed improvements in psychological
functioning and reported medical symptoms. Our outcome
variables included measures of medical and psychological
symptoms shown in previous research to be associated with
significant improvements in MBSR participants (see sec-
tion on measures below). In addition, because meditation
traditions consistently suggest that the practice of mind-
fulness cultivates positive qualities such as wisdom, com-
passion, insight, and equanimity (Shapiro et al. 2002), we
included a measure of psychological well-being (Ryff
1989) that assesses aspects of psychological health inde-
pendent of symptom levels. This measure has not been
included in previous studies of MBSR.
Methods
Participants
Study participants were drawn from individuals enrolled in
the University of Massachusetts Medical School MBSR
program in Worcester MA during 2006. While detailed
data were not available on participants’ diagnoses, the
MBSR groups included adults with a wide range of prob-
lems including illness-related stress, chronic pain, anxiety,
and personal and employment-relat ed stress. Each class
included approximately 20–25 participants; about half
were referred by their health-care practitioner and others
were self-referred. Participation in the program is on a self-
pay basis. Self-report data for program evaluation and
participant information are routinely collected before the
first class, and again at the end of each 8-week group. All
participants are asked on the intake questionnaire whether
their response information can be used for research pur-
poses, on condition that they are not identified as individ-
uals. The current study includes data from the 96% of the
participants who consented to the use of their data for
research purposes.
A total of 206 individuals in nine MBSR groups who
consented to the use of their data completed the pre-
intervention measures. Of these, 10 (5%) attended three or
fewer sessions and provided no assessment data at post-
intervention. Of the remaining 196, 22 attended four or
more sessions but failed to provide post -intervention
assessment data. Thus, data at both pre- and post-MBSR
were available for 174 participants (85% of those who
consented to participate). Of these, 168 (97%) attended
six or more of the eight weekly sessions, whereas five
participants attended five sessions or fewer. Attendance
data for one participant were unavai lable. The all-day
session in week six was attended by 150 (86%) of these
participants.
The mean age of the 174 participants was 47.05 years
(SD = 10.26, range 19–68) and 63% were female. Most
were married (65%) or cohabitating (9%), whereas 12%
were single, 9% were separated, divorced, or widowed, and
5% did not answer this question. Most participants reported
white collar and professional occupations. Current or pre-
vious participation in psychotherapy was reported by 63%
of the sam ple.
Differences between the participants who failed to
provide post-treatment data (N = 32) and the rest of the
sample (N = 174) were examined using one-way analysis
of variance and chi-square analyses. No significant differ-
ences were found for demographic variables (age, gender,
marital status, participa tion in psychotherapy) or for any of
the dependent variables as measured at pre-treatment
(medical and psychological symptoms, perceived stress,
J Behav Med (2008) 31:23–33 25
123
well-being, mindfulness). Thus, the 174 participants
included in analyses described later appear to be repre-
sentative of the slightly larger group that consented to
participate.
Procedures
Prospective MBSR participants attend an orientation/
information session during the three weeks prior to the
beginning of each 8-week group. In these sessions the goals
and format of the program are explained and any questions
they may have about their participation are answered. Pre-
program questionnaires (described below) were completed
immediately prior to these orientation sessions. Post-pro-
gram instruments were completed during the final MBSR
session. Home practice data were derived from a mind-
fulness practice log in which participants recorded the
number of minutes of formal and informal mindfulness
practice they did each day. Participants placed their com-
pleted logs in the slot of a closed purpose-built box that
was in the classroom each week. The study assistant col-
lected the logs from the box following each session.
Respondents were assured that their responses would not
be seen by the instructor. Logs were color-coded by week.
Participants who forgot to bring their log to class were
asked to fill out a retrospective plain white log for that
week.
Measures
Demographic characteristics were assessed at pre-inter-
vention only. Participants reported their age, gender, mar-
ital status, occupation, any history of substance abuse, and
past or current participation in psychotherapy.
Variables assessed at both pre- and post-MBSR
included mindfulness, medical and psychological symp-
toms, perceived stress, and psychological well-being.
Home mindfulness practice was assessed throughout the
intervention.
Mindfulness was assessed using the FFMQ (Baer et al.
2006). This instrument was derived from a factor analysis
of questionnaires measuring a trait-like general tendency to
be mindful in daily life. It consists of 39 items assessing
five facets of mindfulness: observing, describing, acting
with awareness, non-judging of inner experience, and non-
reactivity to inner experience. Items are rated on a Likert
scale ranging from 1 (never or very rarely true) to 5 (very
often or always true). The FFMQ has been shown to have
good internal consistency and significant relationships in
the predicted directions with a variety of constructs related
to mindfulness (Baer et al. 2006).
Home mindfulness practice was assessed using a folder
of seven color-coded homework logs––one color for each
of the seven weeks of the MBSR program. Participants
were asked to record the number of minutes of home
practice they did each day in each of the formal meditation
practices taught in the program (body scan, mindful yoga,
sitting meditation) as well as the minutes of informal
(becoming mindful in everyday activities) practice.
Psychological symptoms were assessed with the Brief
Symptom Inventory (BSI) (Derogatis 1992) which include s
53 items and provides nine sub-scale scores measuring a
range of psychological symptoms and somatic complaints.
A global severity index (GSI) also can be calculated.
Studies of MBSR show significant reductions in GSI,
anxiety and depression associated with participation in the
program (Shapiro et al. 1998; Williams et al. 2001; Ma-
jumdar et al. 2002).
Medical symptoms were assessed using the Medical
Symptom Checklist (MSCL) (Kabat-Zinn 1982). This is a
list of 115 common medical symptoms and respondents
are asked to check those they have experienced as both-
ersome in the past month. The score is the total number
of symptoms checked. While the reliability and validity of
the MSCL have not been evaluated, several studies of
MBSR have shown significant reductions in the MSCL
associated with participation in the program (Kabat-Zinn
et al. 1985; Kabat-Zinn 1987; Kabat-Zinn and Chapman-
Waldrop 1988; Kabat-Zinn et al. 1992; Williams et al.
2001).
Perceived stress was assessed using the Perceived
Stress Scale (PSS) (Cohen et al. 1983; Cohen and
Williamson 1988), a widely-used and well-validated
10-item scale that measures the degree to which situa-
tions in one’s life over the past month are appraised as
unpredictable, uncont rollable and overwhelming. It pos-
its that people appraise potentially threatening or chal-
lenging events in relation to their available coping
resources. A higher score indicates a greater degree of
perceived stress. Participation in MBSR has been asso-
ciated with significant declines in PSS scores (Carmody
et al. 2006).
Psychological Well-Being was assessed using the Scales
of Psychological Well-Being (Ryff and Keyes 1995) which
conceptualize psychological well-being (PWB) as has
having six elements: self-acceptance (positive attitude
toward one’s self, life, and past, including good and bad
qualities), positive relations with others (warm, satisfying,
trusting relationships), autonomy (independence , ability to
resist social pressures and follow own standards), envi-
ronmental mastery (competence in managing life’s
demands), purpose in life (goals and direction, sense of
meaning), and personal growth (view of self as growing
and developing, openness to new experiences). The PWB
scales measure these six elements and are available in
several lengths. The 54-item version, with nine items per
26 J Behav Med (2008) 31:23–33
123
scale, was used in the present study. This version has been
shown to have good psychometric properties (Sewell et al.
2004). We used a total score derived by summing the
elements of well-being.
Results
Changes in mindfulness facets, well-being, perceived
stress and symptoms
Changes in all variables from pre- to post-MBSR
(N = 174) can be seen in Table 2. Paired sample t-tests
showed that all variables changed significantly and in the
expected direction. Pre-post effect sizes (Cohen’s d) were
calculated using the formula suggested by Rosenthal
(1984) for matched-pairs data (d = t/"df). Scores on all
mindfulness facets increased significantly pre- to post-
program. Effect sizes were large for observing and non-
reactivity to inner experience and moderate for describing,
acting with awareness, and non-judging. Psychological
well-being subscales also increased significantly in asso-
ciation with program participation, and showed a large
effect size. Medical and psychological symptoms and
perceived stress levels all decreased significantly, with
moderate to large effect sizes.
Home mindfulness practice
Of the 174 participants who provided both pre- and post-
MBSR assessment data, 121 (69.5%) provided some or all
of their home practice data. Only these 121 participants are
included in the following analyses of practice time. For
these 121 participants, the mean number of practice logs
provided was 6.16 out of a possible seven (SD = 1.34), and
91% provided five or more of the seven logs. For missing
logs, values of zero were entered. Thus, practice times may
be under-estimates, as participants may have engaged in
mindfulness practice on days for which they completed no
logs.
For each of the formal practices, a mea n of 97.7% of
reported practice times fell between 0 and 45 min. Nearly
all of the remaining practice times fell between 46 and
90 min. A few individuals occasionally reported practicing
one particular exercise on one specific day for
100–300 min. These latter reports, although extreme,
Table 2 Means and SD’s, paired sample t-tests, and pre-post effect sizes for all variables
Variable Pre-MBSR Post-MBSR t d
M SD M SD
Mindfulness facets
Observe 23.79 5.84 28.28 4.72 –11.94** .91
Describe 26.90 6.42 28.92 6.02 –6.12** .47
Act with awareness 23.72 5.76 26.49 5.13 –7.60** .58
Nonjudge 26.34 7.01 30.78 5.86 –8.70** .68
Nonreact 17.97 4.98 22.19 4.13 –11.09** .86
Psychological well-being 227.62 37.41 246.55 37.95 –9.77** .77
Perceived stress 22.13 6.19 15.78 6.33 13.14** 1.02
Symptom measures
MSCL 21.63 12.09 13.66 9.77 11.83** .90
BSI-global severity 0.77 0.47 0.53 0.40 8.38** .65
Somatization 0.55 0.57 0.42 0.48 3.54* .27
Obsessive-compulsive 1.34 0.82 0.96 0.68 7.61** .58
Interpersonal sensitivity 0.92 0.85 0.62 0.64 5.86** .45
Depression 0.81 0.70 0.57 0.65 5.64** .44
Anxiety 1.04 0.74 0.65 0.53 7.84** .61
Hostility 0.75 0.65 0.46 0.46 6.84** .53
Phobic anxiety 0.32 0.51 0.17 0.38 3.83** .30
Paranoia 0.55 0.61 0.41 0.46 4.15** .32
Psychoticism 0.54 0.54 0.37 0.45 4.99** .39
Note. MSCL = Medical Symptom Checklist, BSI = Brief Symptom Inventory
* p < .01, ** p < .001
J Behav Med (2008) 31:23–33 27
123
represented less than .05% of all reported practice times.
To normalize the distribution of practice times and reduce
the potential influence of outliers on the analyses that fol-
low, reported daily practice times for each exercise were
coded on a 0–10 scale, in which 0 = no practice,
1 = 1–5 min of practice, 2 = 6–10 min, 3 = 11–15 min,
and so on, with 10 = greater than 45 min of practice.
Participants were encouraged to engage in out-of-class
practice 6 days per week and homework practice logs were
requested at sessions two through eight (seven weeks)
yielding a maximum total number of 42 expected practice
days. While the sequence of introduction of the formal
mindfulness techniques could vary in individual classes at
the discretion of the instructor, generally during the first
two weeks participants were asked to practice the body scan
6 days per week. Mindful yoga was introduced in the third
session and participants were asked to practice the body
scan and yoga on alternate days during the following two
weeks. While short sitting meditation periods were intro-
duced during the first four sessions and participants were
encouraged to practice this at home, the 45-min recording
of guided sitting meditation was not introduced until the
fifth session. At that time, participants were instructed to
practice the sitting meditation on alternate days, with their
choice of either the body scan or the yoga on the inter-
vening days. After that, they were given considerable
flexibility to choose which exercise(s) to practice each day.
Table 3 shows the mean number of days on which
participants reported practicing each exercise, together
with the mean duration (in min) of practice on each of
those days, and the total number of hours of practice over
the course of the program. On the average, participants
reported practicing the body scan on 19.6 days, for
31–35 min each day that they practiced it. Participants
practiced yoga on nearly 17 days, for 16–20 min per day.
Sitting meditation was reported on roughly 20 days, for
16–20 min per day. Many participants reported engaging in
more than one formal practice on a single day. The average
number of days on which any formal practice occurred
(body scan, sitting, and/or yoga) was 33.55, or 80% of the
42 assigned days of practice. The average total practice
time for all formal practices combined was 31–35 min per
day. Informal practice (becoming mindful in everyday
activities) was reported on a mean of just under 20 days,
for an average of 11–15 min per day.
Relationships between home mindfulness practice
and other variables
We examined whether time reported spent in mindfulness
practice was related to the extent of change in mindfulness,
well-being, and medical and psychological symptoms. For
these analyses, daily homework practice times (coded on
the 0–10 scale described above) for each exercise were
summed, yielding a total reported practice time for each
exercise over the course of the 7-week program.
Table 4 shows correlations between total practice time
and pre-post changes in all dependent variables. Because of
the large number of correlations present ed, only those with
p values less than .01 are considered significant. These
findings suggest that practice time for formal meditation
(body scan, yoga, sitting) is associated with many changes
in the beneficial direction. Practice of the body scan was
significantly related to increases in the mindfulness facets
of observing and non-reactivity to inner experience,
increases in psychological well-being, and decreases in
interpersonal sensitivity and anxiety. Yoga practice was
significantly associated with changes in four of five
mindfulness facets (all but describing), well-being, per-
ceived stress levels, and several types of psychological
symptoms. A similar pattern was seen for total formal
practice time (body scan, sitting, and yoga combined).
Practice of sitting meditation was significantly associated
with changes in two mindfulness facets (acting with
awareness and non-reactivity), psychological well-being,
and symptoms of psychoticism (social alienation and
concerns about the health of one’s mind). In contrast,
reported informal mindfulness practice (doing routine
activities mindfully) showed no significant relationships
with changes in any of the dependent variables. In addi tion,
changes in the describing facet of mindfulness were not
related to practice times for any of the mindfulness exer-
cises. No significant correlations were found between
practice time and change in medical symptoms.
Table 3 Homework practice during MBSR course for 121 participants providing homework data
Mindfulness exercise Total days practiced Minutes per day practiced Total hours practiced
Mean SD Mean Minimum Maximum
Body scan 19.61 9.32 31–35 6–10 >45 10.79
Movement (yoga) 16.92 11.14 16–20 1–5 41–45 5.08
Sitting meditation 19.70 10.98 16–20 1–5 41–45 5.91
Any formal practice 33.55 10.87 31–35 6–10 >45 18.45
Informal practice 19.94 13.69 11–15 1–5 >45 4.3
28 J Behav Med (2008) 31:23–33
123
Although these findings sugges ted that greater practice
time is associated with increases in mindfulness and well-
being and decreases in stress and symptoms, it was
important to consider whether pre-treatment levels of
mindfulness or psychological functioning were related to
participants’ likelihood of engaging in their assigned
homework exercises. Correlations were therefore com-
puted between total formal practice time during the inter-
vention and pre-treatment scores on the mindfulness facets,
perceived stress, medical and psychological symptoms, and
well-being. These correlations were non-significant, sug-
gesting that participants’ pre-treatment levels of these
variables had no significant effect on the amount of
assigned home mindfulness practice they reported doing.
Mediation analyses
Because the findings suggested that engaging in formal
mindfulness practices was associated with improvements in
both mindfulness and symptoms/well-being, our third goal
was to test the hypothesis that increases in mindfulness
mediate the relationship between reported minutes spent in
practice and improved psychological functioning. To
examine this question we conducted three mediation
analyses using the methods based on linear regression
described by Baron and Kenny (1986), supplemented with
methods described by MacKinnon et al. (2000). In each
case the independent variable (IV) was total formal prac-
tice time over the course of the program, created by sum-
ming the practice times (coded 0–10 as described earlier)
for body scan, sitting meditation, and yoga. Informal
practice time was not included in this variable because it
was not significantly correlated with changes in other
variables. The proposed mediating variable was the degree
of change in mindfulness from pre- to post-intervention
and was created by summing the pre-post change scores for
the observing, acting with awarene ss, non-judging, and
non-reactivity facets. The describing facet was not
included in this variable because it was not significantly
correlated with practice time. The dependent variables
(DV) for the three mediation analyses were pre-post
change scores for psychological symptoms (BSI-global
severity index), perceived stress (PSS total score), and
psychological well-being (PWB total score), respectively.
According to Baron and Kenny (1986), several condi-
tions must be met to show support for a mediational
hypothesis. The IV, mediator, and DV all must be signifi-
cantly inter-correlated. When the IV and the mediator are
entered simultaneously into a model predicting the DV, the
relationships between the IV and DV must become non-
significant, or must be significantly reduced. For the first
mediation analysis, in which decrease in psychological
Table 4 Correlations between total practice time during MBSR course and pre-post changes in other variables for 121 participants providing
homework data
Body scan Movement (yoga) Sitting meditation Total formal practice Informal practice
Mindfulness facets
Observe .29* .24* .23 .33* .21
Describe .02 .02 .04 .03 .02
Act with awareness .09 .32* .26* .27* .14
Nonjudge .08 .26* .09 .18 .03
Nonreact .28* .32* .26* .36* .09
Psychological well-being .27* .42* .32* .42* .21
Medical symptoms .17 .19 .12 .21 .03
Perceived stress .16 .24* .23 .26* .15
Psychological symptoms
Somatization .14 .14 .12 .17 –.02
Obsessive-compulsive .10 .13 .03 .12 .06
Interpersonal sensitivity .24* .31* .19 .31* .08
Depression .05 .18 .15 .15 .01
Anxiety .26* .25* .19 .29* .09
Hostility .04 .06 –.02 .04 –.12
Phobic anxiety .15 .33* .16 .26* .21
Paranoia .06 .17 .11 .14 –.09
Psychoticism .22 .33* .27* .33* .10
Global severity .21 .32* .19 .30* .02
* p < .01
J Behav Med (2008) 31:23–33 29
123
symptoms was the dependent variable, all conditions were
met. Meditation practice time was a significant predictor of
decrease in psychological symptoms (R = .30, F = 11.39,
p < .01), and of increase in mindfulness (R = .42,
F = 21.95, p < .001). Increase in mindfulness also was a
significant predictor of decrease in symptoms (R = .49,
F = 46.50; p < .001). When formal practice time and
increase in mindfulness were entered simultaneously as
predictors of decrease in symptoms, the regression coeffi-
cient for practice time dropped to .10 (ns). According to the
formula described by MacKinnon et al. (2000), the drop in
the regression coefficient from .30 to .10 is significant
(t = 3.57, p < .01). This result is consistent with the
hypothesis that the relationship between practice time and
psychological symptoms is completely mediated by
increases in mindfulness skills. This analysis can be seen in
Fig. 1a.
A similar pattern was found for the second mediation
analysis, in which decrease in perceived stress was the
dependent variabl e. (Fig. 1b). In this case, meditation
practice time was a significant predictor of decrease in
perceived stress (R = .26, F = 8.30, p < .01) and of
increase in mindfulness (R = .42, F = 46.50, p < .001).
Increase in mindfulness also was a significant predictor of
decrease in perceived stress (R = .44, F = 34.74, p < .001).
When formal practice time and increase in mindfulness
were entered simultaneously as predictors of decrease in
perceived stress, the regression coefficient for practice time
dropped significantly (t = 2.77, p < .01) to .12 (ns), sug-
gesting that the relationship between practice time and
perceived stress also is completely mediated by the
development of mindfulness skills.
For increase in psychological well-being, only partial
mediation was shown (Fig. 1c). In this case, meditation
practice time was a significant predictor of well-being
(R = .42, F = 24.14, p < .001) and of increase in mind-
fulness (R = .42, F = 21.95, p < .001). Increase in mind-
fulness also was a significant predictor of well-being
(R = .49, F = 45.95, p < .001). However, when practice
time and increase in mindfulness were entered simulta-
neously as predictors of well-being, the relationship
between practice time and well-being remained significant,
although the drop in the regression coefficient from .42 to
.25 was significant (t = 3.87, p < .01). This finding sug-
gests that, although increases in mindfulness are important
in accou nting for improvements in well-being, other vari-
ables not included in the model may also be important in
accounting for increased well-being.
Discussion
The first goal of this study was to investigate whether
participation in MBSR would lead to changes in levels of
mindfulness as measured by the FFMQ. If such changes
were observed, the second goal was to examine whether
extent of home practice of mindfulness meditation was
related to change s in mindfulness as well as changes in
symptoms and well-being. Finally, if these relationships
were found, the third goal was to explore whether increases
in mindfulness mediate the relationship between medita-
tion practice and improvements in functioning. Results
showed that levels of mindfulness increased significantly
from pre- to post-MBSR, with effect sizes in the moderate
to large range. Results also showed that the extent of home
practice of formal meditation exercises (body scan, yoga,
sitting) is significantly correlated with degree of change in
most facets of mindfulness (all but describing), and several
measures of symptoms and well-being, although informal
mindfulness practice (doi ng routine activities mindfully)
Increase in
mindfulness
.42* .49*
(FFMQ)
Total formal
practice time
Decrease in
psychological
symptoms (BSI-
GSI)
(.10) .30*
Increase in
mindfulness
.42* .44*
(FFMQ)
Total formal
practice time
Decrease in
perceived stress
(PSS)
(.12) .26*
Increase in
mindfulness
.42* .49*
(FFMQ)
Total formal
practice time
Increase in
psychological
well-being
(PWB)
(.25*) .42*
a
b
c
Fig. 1 Mediation of the relationship between formal meditation
practice time and pre-post decrease in psychological symptoms as
measured by the BSI-GSI (a), pre-post decrease in perceived stress as
measured by the PSS (b), and pre-post increase in psychological well-
being as measured by the PWB total score (c). In each case, the
mediating variable is the sum of pre-post change scores in the
observing, acting with awareness, nonjudging, and nonreactivity
facets of mindfulness. All values are beta coefficients. Values in
parentheses show relationships between formal practice time and the
dependent variable, when the mediating variable is included in the
model. *p < .01
30 J Behav Med (2008) 31:23–33
123
was unrelated to these outcomes. Finally, increases in
mindfulness were shown to completely mediate the rela-
tionships between meditation practice over the course of
the intervention and improvement in psychological symp-
toms and perceived stress, suggesting that the improve-
ments in mindfulness that appear to result from regular
practice are related to the significant reductions in psy-
chological distress and perceived stress that were observed.
Because perceived stress and symptom scores were sig-
nificantly inter-correlated at both pre- and post-interven-
tion, it is not surprising that mediation analyses for these
two variables showed similar findings. Psychological well-
being also was significantly intercorrelated with stress and
symptoms, yet only partial mediation was shown for this
variable, suggesting that other variables not measured here
are important in accounting for the relationship between
formal practice time and increased well-being.
These findings are important because they provide initial
support for a central tenet of several mindfulness-based
treatment approaches: that the regular practice of medita-
tion should cultivate mindfulness skills in everyday life,
which in turn should lead to improved psychological
functioning such as symptom reduction, reduced stress and
enhanced well-being. While this expectation is well
established in the Buddhist meditation traditions upon
which these programs draw, there is limited empirical
evidence for the claim in clinical settings (Ramel et al.
2004; Toneatto and Nguyen 2007) and this is the first study
to report these associations with a large sample in a clinical
context. An alternative explanation––that more mindful
people are more likely to practice meditation––was not
supported by our findings, which showed non-signifi cant
relationships between baseline levels of mindfulness and
extent of home practice duri ng the intervention. The find-
ings also provide encouraging support for the validity and
utility of the FFMQ in measuring mindfulness. While
significant improvements were noted in the describing
factor of the FFMQ, these changes were not significantly
associated with reported practice. This may be because
MBSR training does not emphasize verbal labeling of the
components of experience to the extent seen in some other
mindfulness-based interventions, such as DBT and ACT,
which include exercises for labeling of emotions, cogni-
tions, and sensations.
An unexpected finding was the strong association
between the mindful yoga form of practice and changes in
other variables, including increased mindfulness skills,
reduced symptoms, and improved well-being. Practice time
for mindful yoga was significantly correlated with more of
these variables than were practice times for the body scan
or sitting meditation, and yoga was the only formal prac-
tice significantly related to increases in the non-judging
facet of mindfulness and the global severity index of the
BSI. Given that mindful yoga was practiced on fewer days
and for fewer total hours than the other formal practices,
these results are striking and bear further investigation. As
the body scan is assigned for daily practice during the first
two weeks and is also a somatically-oriented practice, it
may be that the time participants spent in practice of the
body scan prepared them to be more mindful of their
bodily sensations during the yoga, and hence obtained
more benefit from the yoga practice than if they had come
to it without prior mindfulness practice. It may also be
easier for participants to bring mindful attenti on to the
body while it is moving or stretching as the yoga requires,
than while it is still as in the body scan or sitting medita-
tion, and this feature may also facilitate the transfer of the
resultant mindfulness into everyday life. The considerably
higher average number of reported minutes of body scan
practice than the average yoga and sitting practice may
represent the initial novelty of practice in the early weeks
of participation in the program, which may have waned
over subsequent weeks.
Another unexpected finding was the lack of significant
relationships between informal practice (doing routine
activities mindfully) and extent of change in other vari-
ables. Informal practice is often described as an important
method for generalizing mindfulness skills learned in for-
mal practices into daily life (Kabat -Zinn 1990). Since no
audio reco rdings are provided to guide informal practice, it
is possible that participants in this study had difficulty in
providing accurate estimates of the time they spent in
informal practice. Better methods of monitoring this type
of practice may be helpful in future studies as well as a
more detailed investigation of the importanc e of ‘living
mindfully’ on health and well-being outcomes.
Several symptom measures, including the Medical
Symptom Checklist and several scales of the BSI, showed
significant improvements from pre- to post-MBSR that
were not correlated with the amount of home practice of
any of the mindfulness exercises. Home practice is not the
only mechanism by which improvements may be obtained
in MBSR and it is possible that reductions in these
symptoms can be attributed to other potentially important
factors not measured here, such as social support from
other group members, caring attention from the group
leader, the effect of mindfulness together with the physical
exercise that comes from yoga, or improved ability to
relax. Further, a person who undertakes the commitment of
a course such as MBSR may also be motivated to con-
currently prac tice other mind-b ody techniques or to change
or improve other health-related behaviors such as medi-
cation and treatment compliance for existing medical or
psychological conditions. Future research should attempt to
measure these variables, so that other potential mechanisms
of change can be studied.
J Behav Med (2008) 31:23–33 31
123
The following limitations of the study should be con-
sidered. Most of the participants were well educated, had
the financial resources to pay for the treatment and had
agreed to take part in a meditation-based program. It cannot
be assumed that these findings can be generalized to other
populations. In addition, the reported home practice figures
should be interpreted with some caution. These analyses
included only those participants (N = 121) who provided
some or all of their practice data, and values of zero were
entered for days for which practice records were not com-
pleted. Although instructors did not look at these forms,
which were filed by research assistants, participants may
have been less likely to complete a prac tice form for weeks
in which they engaged in less homework practice. Thus, if
all homework sheets had been completed, average daily
practice times might have been lower. On the other hand, if
the missing homework sheets had been turned in, and had
included values greater than zero, then the figures for total
practice time would have been higher. Thus, the figures we
used are probably conservative estimates of practice time.
In addition, a very small number of reported practice times
were extremely high (e.g., 100–300 min of a single exercise
on a sing le day). Because there was no significant correla-
tion between reported practice time and baseline symptom
levels, it does not appear that the more severely impaired
participants were more likely to practice. Thus, the reasons
for these unusual practice times are unclear.
The lack of a control group for this study is also a
limitation, The efficacy of MBSR in reducing psycholog-
ical distress and symptoms of stress has however been
shown in previous controlled studies (Shapiro et al. 1998;
Speca et al. 2000; Grossman et al. 2004). While the
dependent variables in the mediation analysis were change s
in symptoms and well-being the primary focus of the study
was an examination of the relationships between home
practice of mindfulness exercises and change in these
outcomes, as well as the relationship of home practice to
changes in levels of mindfulness. This latter relationship
has not previously been reported. Never the less, the lack of
another behavioral program as a suitable control interven-
tion means that our study sheds no light on whether other
interventions would result in similar changes. Other stress
reduction programs may not require meditation, but they
are likely to involve the practice of relaxation and/or
cognitive restructuring and it is not known whether such
practices lead to increases in mindfulness. Therefore future
research should compare MBSR to other stress reduction
programs to clarify whether the suggested mechanisms
leading to improvement are unique to MBSR and also
to assess the potential confounding impact of other
health-related behaviors that may also change in partici-
pants motivated to undertake such programs.
Acknowledgements The authors would like to acknowledge the
assistance of staff in the Center for Mindfulness for administrative
support and data entry.
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James Carmody is Assistant
Professor of Medicine at the
University of Massachusetts
Medical School, and Director of
Research for the Center for
Mindfulness. His research
interests are in mind-body
medicine and the role of atten-
tional processes in health and
well-being.
Ruth A. Baer is Professor of
Psychology at the University of
Kentucky. Her research inter-
ests include mindfulness and
acceptance-based interventions,
assessment and conceptualiza-
tion of mindfulness, cognitive-
behavioral interventions, and
psychological assessment.
J Behav Med (2008) 31:23–33 33
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