Mindfulness-Based Intervention Effects on Substance Use and Relapse Among Women in Residential Treatment: A Randomized Controlled Trial With 8.5-Month Follow-Up Period From the Moment-by-Moment in Women’s Recovery Project

OBJECTIVE: We tested the efficacy of Moment-by-Moment in Women’s Recovery (MMWR), a mindfulness training program adapted for ethnoculturally diverse women with complex social and clinical histories in residential treatment for substance use disorder, on substance use and relapse outcomes. METHODS: Participants were randomized to MMWR (n = 100; 60% Hispanic/Latina, 18% non-Hispanic Black) or the attention control condition, Neurobiology of Addiction (n = 100; 56% Hispanic/Latina, 21% non-Hispanic Black). Substance use outcomes (days until first use, days of use, and relapse status: abstained, lapsed, relapsed) were obtained from interviewer-assisted timeline followback for an 8.5-month follow-up period spanning the intervention start through the 6-week intervention period and 7 months after the intervention ended. RESULTS: An intent-to-treat survival analyses showed that time delay to first marijuana use favored MMWR (hazard ratio = 0.44, 95% confidence interval = 0.20–0.98, p = .049) with a medium-to-large effect size. In negative binomial hurdle models, the MMWR group showed fewer days of marijuana use at 3.5 months (B = −1.71, SE = 0.79, incidence rate ratio = 0.18, p = .030) and a trend at 7 months after the intervention (B = −0.90, standard error = 0.55, incidence rate ratio = 0.41, p = .10). For marijuana, mindfulness practice time during the intervention predicted time delay to first use (B = 0.28, p = .006) and total abstinence days (B = 0.34, p = .002) across the 7 months after MMWR. No other substance use outcomes showed differential response to MMWR relative to controls. Only in MMWR, number of study intervention sessions attended (dose) correlated with a greater length of time to alcohol intoxication (r = .48, p < .001), fewer days of alcohol intoxication (r = −.24, p = .020), and greater improvement in mindfulness skills (r = .61, p < .01). CONCLUSIONS: MMWR added to an ongoing intensive residential treatment program serving vulnerable women is protective against marijuana use but no other substance use outcomes. Mindfulness practice time predicted a delay in time to first marijuana use. MMWR class attendance, an indicator of intervention dose, appears protective of alcohol intoxication at follow-up; thus, extended MMWR exposure might be useful.