LAUSR

Objectives Mindfulness-based relapse prevention (MBRP) for substance use disorders (SUDs) appears to be particularly effective among individuals with high levels of co-occurring affective symptoms. We sought to understand whether changes in approach and avoidance coping may explain the effects of MBRP among this subpopulation. Method The sample included 286 individuals with SUDs randomized to MBRP, relapse prevention (RP), or treatment-as-usual (TAU) as an aftercare treatment. We conducted conditional indirect effect models with treatment condition as the predictor, baseline affective symptoms as the moderator, changes in approach and avoidance coping over time from baseline through 6-months post-treatment as mediators, and substance use and substance-related problems at 12-months post-treatment as the outcome. Affective symptomatology at baseline was modeled as a latent factor indicated by depression, anxiety, and PTSD symptoms. Change in approach and avoidance coping was modeled using latent growth curve analyses. Results We found significant conditional indirect effects of MBRP, such that the interaction of MBRP vs. TAU by affective symptoms predicted increases in approach coping, which in turn predicted fewer heavy drinking days and substance-related problems at month 12. Follow-up analyses showed that increases in approach coping mediated the therapeutic effect of MBRP on these outcomes among those with high, but not low or moderate, affective symptoms. We did not find indirect or conditional indirect effects when comparing RP to TAU, or when avoidance coping was the mediator. Conclusions The pronounced therapeutic effects of MBRP among individuals with SUD and relatively higher negative affective symptoms may be due to increases in approach coping over time.