A combined analysis of two randomized controlled trials evaluating the effect of Mindfulness-Based Stress Reduction on self-reported emotional experience and physiological symptoms among Veterans with Posttraumatic Stress Disorder

Thesis (Master's)--University of Washington, 2016-06

Background: Approximately 13% of military veterans meet diagnostic criteria for Posttraumatic Stress Disorder (PTSD), indicated by the presence of emotional numbing and behavioral avoidance, re-experiencing the traumatic event (e.g. through flashbacks or nightmares), hyper-vigilance, and cognition and mood disturbances. Since individuals with PTSD often experience additional problems that affect their quality of life, such as anger, fatigue, and depression, worsened physical and social functioning, and compromised sleep quality, new treatments are needed for PTSD that improve multiple domains of health in addition to PTSD symptoms. Methods & Analysis: Data from two randomized control trials comparing Mindfulness-Based Stress Reduction (MBSR) to a treatment-as-usual (TAU) control group among a sample of veterans with PTSD were analyzed in a combined analysis. Data measuring PTSD severity, mindfulness, and eleven different health domains were collected at baseline, post-MBSR, and 4 to 6-month follow-up. PTSD was measured with the PTSD Checklist civilian version (PCL-C) in one study and with the PTSD Symptom Scale Interview (PSS-I) in the other; mindfulness was measured with the Five Facet Mindfulness Questionnaire; and the eleven health domains were measured with the National Institutes for Health Patient-Reported Outcome Measurement Information System (PROMIS). An intent-to-treat analysis compared post-intervention and follow up outcomes for all subjects randomized to MBSR to all subjects randomized to TAU, and a completer analysis compared outcomes between MBSR completers (those who completed at least 4 sessions of MBSR) to the TAU group. Results: A significantly greater proportion of those randomized to MBSR reported a clinically significant decline in PTSD symptoms compared to those randomized to TAU at post-intervention (52.8% compared to 20.5%, p<.005), but this difference was not maintained at follow-up. In the intent-to-treat analysis, there were no statistically significant differences in all eleven PROMIS health domain outcomes at post-intervention or follow-up between those randomized to MBSR plus TAU and those randomized to TAU only. In the completer analysis, the MBSR group reported significantly better outcomes than TAU for pain interference (mean difference between groups, -5.20; 95% CI, -10.17 to -0.24, p<.05), and significantly worse outcomes than TAU for physical function at the 4 to 6-month follow-up (mean difference, -7.12; 95% CI, -14.2 to -0.01, p=.05). The completer analysis found significantly greater improvements for overall mindfulness at post-intervention (mean difference, 11.41; 95% CI, 1.35 to 21.46; p<.05) and follow-up (mean difference, 13.11; 95% CI, 3.06 to 23.15; p<.05) among those in MBSR than those in TAU. Conclusions: Although our findings indicate that participation in MBSR resulted in increased overall mindfulness and a few specific mindfulness skills, it is unclear whether these skills are directly related to the decline in PTSD symptoms or the trends toward improvement in the PROMIS health domains in the MBSR groups compared to TAU. Additional research is warranted to further explore the impact of mindfulness-based interventions on PTSD symptoms and the potential role of mediating factors.