410913
Mindfulness Training to Emotional Regulation and Physical Health Outcomes
Considerable empirical evidence indicates that emotional dysregulation
adversely affects mental and physical health. For example, higher levels of emotion
dysregulation is associated with greater difficulties in interpersonal relationships (e.g.,
Wei et al., 2005), more substance abuse (Hayes et al., 1996), and higher rates of inflicted
self-injury (Gratz & Roemer, 2003). Thus improving abilities for regulating emotions
should improve these outcomes. Emotional regulation is a construct that refers to
strategies that allow an individual to meet situational demands and achieve individual
goals when emotional arousal occurs, by either by adjusting one's emotional arousal
level or by engaging in effective behaviors (and inhibit impulsive behaviors) despite the
presence of emotions (Gratz & Roemer, 2003).
Mindfulness is a strategy that is thought to improve emotion regulation by
helping individuals relate effectively to their thoughts, emotions, behaviors, and life
situations. Empirical evidence has supported the conclusion that mindfulness improves
emotional regulation (REF needed). Mindfulness training has been used to treat stress,
pain, and physical illness (Center for Mindfulness in Medicine, Healthcare, and Society,
2004), but limitations in the research methodologies precluded clear conclusions about
the efficacy of mindfulness interventions for improving physical health. The current
studies have largely been poorly controlled non-randomized designs, and have failed to
verify if improvements are due to improved emotion regulation. Furthermore, there are
few studies examining whether improving emotion regulation abilities improves
physical health. Thus, further studies are needed to establish internal and construct
validity of mindfulness interventions to improve physical health, and to establish the
role of emotion regulation.
This study will be a randomized controlled trial to examine if mindfulness
training can improve physical health, and whether physical health improves because
improved emotional regulation abilities lead to reductions in emotional dysregulation.
Lowering levels of emotional activation should improve immune functioning by
decreasing harmful stress neurochemicals. If a relationship exists between these
constructs as the literature implies, examining the relationship would be very useful in
improving both mental health and physical illness, and thus the quality of life.
Hypotheses
H1. Mindfulness training will improve physical health.
H1a. Larger increases in HS-36 scores will be found for the mindfulness training
condition than for the control condition.
H2. Changes in emotion regulation abilities will mediate the effect of mindfulness
training on physical health.
H2a. Subjects in the mindfulness training condition will report more emotional
regulation abilities, as measured by the DERS, than the control condition.
H2b. Larger increases in emotion regulation will be associated with larger
increases in physical health, as measured by the HS-36.
H2c. The magnitude of the difference in HS-36 scores between treatment groups
will decrease after DERS scores are entered as a covariate.
H3. Gender will moderate the relationship between treatment and health outcomes.
The mindfulness intervention will be less effective for men.
H3a. Among women, increases in HS-36 scores will be found for the mindfulness
training condition than for the control condition.
H3b. Among men, the difference in HS-36 change scores between conditions will
be smaller than the difference between conditions among women.
Methods
Participant Selection
Inclusion criteria:
 Current health problems (SF-36HS scores above 30)
 Difficulties with emotion regulation (DERS score above 30)
 Age 18 to 55 (because the reliability and validity of the DERS measure has only
been established for this age range; Gratz & Roemer, 2003).
Exclusion criteria:
 Significant physical health problems that are not likely related to emotion
regulation abilities will be an exclusion criterion. The following disorders will be
excluded: dementia [full list is needed].
 Inability so speak English
The subjects will be recruited at various locations in San Diego: local universities,
hospitals, grocery stores, and apartment buildings. The recruitment ad will briefly
describe the study and the incentives of food and twenty dollars per testing session.
Procedures
A stratified block randomization will be used to match subject on gender (2 levels), and
pre-treatment health (SF-36SH, 3 levels), and emotional regulation (DERS, 2 levels).
All outcome measures will be completed pre-treatment and at the 6-month
follow-up assessment. All measures will be administered by interviewers who are naïve
to the treatment condition of subjects, and at the end of the final assessment the
interviewers will check to see that they do not guess the treatment condition of each
subject above chance levels. After the pre-treatment assessments, the experimental
group will receive a mindfulness intervention. The control group will not be provided
any intervention. As a manipulation check all subjects will report the extent of their
participation in mindfulness training (from any source) and home practice.
Furthermore, the qualify of the mindfulness training will be checked by an independent
mindfulness expert.
Outcome Measures
Difficulties in Emotional Regulation (DERS; Gratz & Roemer, 2003) measures
emotion regulation. The DERS is a 36 item self-report measure, using a five point Likert
scale. A high score on the DERS measure reflects more dysregulation of the individual
than a low score. The test has eight subscales, all of which demonstrate similar
reliability to the primary scale. There is evidence of high internal consistency, test-retest
reliability, and convergent validity (Gratz & Roemer, 2003).
Short Form 36 Health Survey (SF-36HS; Ware, Kosinski, & Keller, 1994) is a 36-item
scale that allows individuals to rate their personal health status. The SF-36HS is scored
on a 0-100 scale with higher scores indicating better health. Over 200 studies have
demonstrated its high internal consistency (Ware, Kosinski, & Keller, 1994).
Treatment History Interview (THI; Linehan et al., 1993). The THI will be used to
measure medical services usage, including doctors visits, emergency room visits, and
hospitalizations.
Psychophysiology. Resting heart rate and blood pressure will be measured.
Other Measures
Credibility/Expectancy Questionnaire (CEQ; Borkovec & Nau 1972) will be given after the
pre-treatment assessments and (for the mindfulness group) after the description of the treatment.
The CEQ is a 10-item paper and pencil questionnaire that measures perceived credibility of a
treatement and expectancies that the treatment will lead to improvement. Questions are on a tenpoint (0-9) scale. Four questions are on a eleven-point (0% -100%) scale and asked the how
much improvement in their health and functioning by the end of training do they expect to
happen. The psychometric properties of this intrument have been assessed. Test-retest reliability
was high: expectancy factor (r = .82, p < .001), credibility factor (r = .75, p < .001), and total (r =
.83, p < .001) (Devilly & Borkovec, 2000).
Health Behaviors Questionnaire. This brief investigator-generated self-report questionnaire
will be given at pre-treatment and follow-up to measure frequency of exercise, healthy eating,
and smoking.
Clinical Significance
The magnitude of the effect of the intervention on health outcomes will be
established by evaluating the proportion of subjects in each condition who end up in
the healthy range (SF-36HS scores below 15) and free of serious medical outcomes such
as heart attacks and strokes. Subjects will also be compared on the number of infection
illness episodes.
Internal Validity
The stratified randomization procedure will likely prevent the stratifying
variables, gender and pre-treatment SF-36HS and DERS, from being confounds. Other
variables could be confounds, such as age, SES, marital status, or social support. All
demographic variables and pre-treatment SF-36HS and DERS will be evaluated as
possible confounds. Those variables that show medium effect size group difference and
medium effect size relationship to the follow-up SF-36HS will be included as covariates.
Construct Validity
Because no intervention is provided to the control group it is possible that group
differences in health outcomes may be entirely due to spending time with a
therapist/instructor, getting an intervention designed to improve health. It is likely that
the treatment group will have higher expectancies for health improvement. If
expectancies differ between the two groups, expectancies will be entered as covariates
to see if the mindfulness group has superior outcomes above and beyond expectancies.
Demand characteristics will be limited by describing that the purpose of the
study is to see if emotion regulation improves. Health outcomes will not be
emphasized.
Methods of Testing Mediators and Moderators
The mindfulness intervention may be more effective for women, perhaps
because they are more open to mindfulness and mediation, and self help in general.
This moderator effect will be tested by testing the statistical interaction of gender and
treatment in predicting health outcomes. Women will demonstrate more of an
improvement in their health post test than men. Among women, increases in HS-36
scores will be found for the mindfulness training condition than for the control
condition. However, among men, the difference in HS-36 change scores between
conditions will be smaller than the difference between conditions among women.
Exploratory moderation analyses will be done to see if mindfulness training improves
some health outcomes (e.g., colds and pain) more than others (e.g., sprains and
fractures).
This study will test if emotional regulation abilities mediate the relationship
between mindfulness training and physical health. The mediation theory is that
mindfulness training (and meditation) lowers general levels of emotional activation and
thereby improves immune functioning by decreasing harmful stress neurochemicals.
The following statistical properties will be demonstrated: 1) mindfulness training will
be associated with more improvement in emotion regulation, 2) improvement in
emotional regulation will be associated with improvement in physical health, and 3) the
magnitude of improvement in health between treatment groups will decrease after the
emotion regulation variable is entered as a covariate. Alternative mediation models will
also be tested. It will be tested if the superior outcomes in the mindfulness group could
be due to better health behaviors including exercise, diet, and tobacco abstinence.
Data Analysis Methods
The data in this study will be analyzed with repeated measures ANCOVA with
two tailed tests and .05 alpha level. All variables that show medium effect size group
difference and medium effect size relationship to the follow-up SF-36HS will be
included as covariates. Expectancy scores will also be entered as covariates if
expectancies differ between the two groups. Mediation effects will be tested with a
Sobell mediation analysis, and moderator effects will be tested via interaction effects.
No correction for multiple tests will be applied to avoid Type II errors and since the
analyses are parsimonious.
Power Analysis
Sample size was estimated for a t-test using Cohen’s (1992) power tables. 190
subjects are needed in order to achieve .80 power to detect a small effect size, given twotailed tests and a .05 alpha level. Due to the restrictions of this study it is estimated that
only 70 subjects will participate, which would provide 80% for detecting a large effect
size, and the power would only 60% for detecting a medium effect size and 40% for
detecting a small effect size.
Discussion
Significant finding support the hypothesis that mindfulness training improves
physical health by improving emotion regulation. However significant findings could
also be the result of internal validity confounds. Various baseline differences between
the treatment groups could account for the differential health outcomes if the
extraneous variables are also associated with health outcomes. Possible threats to
internal validity are the differences in baseline health score, age, race, and other
demographic characteristics. Some influential confounds may not have been measured.
For example, the mindfulness group may have started with higher social support than
the control group, and the larger health improvements found in the mindfulness group
could be due to those participants taking better care of themselves (e.g., better diet and
more exercise) because their supportive friends and family encourage and model
healthy behaviors. Measured confounds will be included as covariates, but it is possible
that violations of statistical assumptions (e.g., the homogeneity of regression
assumption) will make this method ineffective for ruling out internal validity
confounds. It is also possible that the superior outcomes for the mindfulness group
have nothing to do with mindfulness training per se. Because no intervention is
provided to the control group it is possible that group differences in health outcomes
may be entirely due to the mindfulness subjects spending time with a supportive
person attempting to provide help, or having more positive health expectancies. The
intervention may be effective, but possibly not for the hypothesized reasons.
If statistically significant differences are not found it could mean that the
mindfulness intervention does not improve emotion regulation or health outcomes.
However, the null results could be due to lack of statistical power; this study is likely to
have an insufficient sample size. To examine this possibility, the effect size (e.g.,
Cohen’s d) of the group differences will be examined. Also, confidence intervals will be
examined to see if meaningful differences are plausible (i.e., within the 95% confidence
interval). It is also possible that the null results could be due to chance (Type II error),
such that there is no outcome difference in this sample although replication of the study
would generally show meaningful differences.
The study probably has reasonable external validity, but results could fail to
generalize to other populations or settings. Mindfulness training may not improve
emotion regulation or physical health for juveniles, the elderly, or non-English
speakers. It is also unknown if the intervention also may not be helpful for people who
are unlikely to volunteer for a research study, perhaps people who are socially isolated
or suspicious, or those with low SES. Future studies must demonstrate that the
intervention generalizes to all of these various populations. To the extent that there are
moderator effects, generalization may be limited. For example, mindfulness training
may not significantly improve emotion regulation or physical health for men, minority
cultural groups, or anybody who does not believe mindfulness is an acceptable or
credible intervention.