The differential impact of two mindfulness components among veterans with posttraumatic stress disorder

Abstract

There is a dearth of empirical research on mindfulness interventions specific to veterans with Posttraumatic Stress Disorder. Of the studies that have been published, most are cross-sectional, have small sample sizes, low statistical power, and used non-randomized designs or no control group. Additionally, dismantling designs employed to discern which specific aspects of mindfulness-based interventions lead to positive outcomes, and subsequently, determine the active ingredients involved in the positive outcomes are lacking. The purpose of this randomized controlled trial was to: a) assess the differential impact of two common components of mindfulness meditation (body scan [BS] and mindful breathing [MB]) on trait and state mindfulness and treatment outcomes compared to an intervention without mindfulness (slow breathing [SB]), and a non-intervention control group (sitting quietly [SQ]); b) explore if changes in mindfulness facets would predict posttreatment outcomes in depression and PTSD for individuals who participated in a mindfulness intervention; and c) investigate if the mindfulness intervention grouping variable (BS v. MB) would moderate the relationship between pre-posttreatment changes in mindfulness facets and posttreatment outcomes in depression and PTSD among a sample of veterans diagnosed with PTSD. Results revealed that BS and MB interventions generally resulted in greater improvements than SB and SQ. Additionally, among participants in a mindful intervention (BS and MB), changes in Nonreactivity, Non-judging, and Acting with Awareness were significant predictors of posttreatment depression. Furthermore, mindfulness group (BS v. MB) moderated the relationship between change in Nonreactivity and post-treatment depression and the relationship between change in Acting with Awareness and post-treatment depression. Simple slope analyses revealed that change in Nonreactivity was a statistically significant predictor of posttreatment depression in the MB group (β = .64, p = .003), but not in the BS group (β = -.12, p = .58), whereas change in Acting With Awareness was a significant predictor of post-treatment depression in the BS group (β =.41, p = .05), but not in the MB group (β =.20, p = .38). The clinical effects of specific components of mindfulness interventions, as well as the discrete mechanism of action within an intervention, will be discussed.