Women's Treatment and Early Recovery

* This randomized clinical trial will deliver two interventions as add-ons to residential substance use disorder (SUD) treatment: (1) Moment-by-Moment in women's Recovery: Mindfulness-Based Approach to Relapse Prevention (MBRP-W) and (2) Brain and Recovery (B\&R) which serves as an active psychoeducational attention control group. * Participants (N=165) who meet study eligibility criteria based on intake assessment will be recruited and complete baseline assessments during weeks 3-6 after entry into a residential treatment program. Participants will be randomly assigned to interventions using Urn randomization. All participants (MBRP-W and B\&R) will receive SUD treatment as normally provided by the treatment program. Fifteen participants from each intervention group (N=30) will be selected to participate in a brain imaging (MRI and fMRI) substudy. * Participants will be adult females who have been admitted to a residential treatment center in an urban area of California and who are diagnosed with a SUD based on clinical intake Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-V) diagnostic assessment. * MBRP-W is delivered in 12 bi-weekly 80-minute group sessions with SUD clinical populations. Facilitators will have previous experience in MBSR facilitation and will be trained in MBRP-W. Each session has a central theme and is divided into five segments consisting of (a) a welcome meditation or other mindfulness practice, (b) a review of session objectives, (c) a brief didactic psycho-educational presentation and discussion based on the session's theme, (d) experiential and formal meditation or other practices, and (e) readings and practice assignments for the next class. * B\&R is delivered in 12 bi-weekly 80-minute group sessions with SUD clinical populations. Facilitators will be trained in B\&R. The B\&R group will receive didactic education on the neurobiology of addiction. B\&R contains no information on behavior change, relapse prevention, stress reduction, or mindfulness-based or relapse-related content. The intervention was developed over three years with a population similar to that of the current study (i.e., racially/ethnically diverse and low-income women in SUD treatment) with input and review from focus group participants, care providers in SUD treatment, and three experts on the neurobiology of addiction. Topics include: (1) brain structure and function related to addiction, (2) effects of various types of substance use on the brain, and (3) rewarding effects of substance use and how these rewarding effects can lead to addiction. * There are three data collection points, 1) baseline, 2) immediate post-intervention, and 3) 8-months post-intervention completion. Data will be collected in-person by research interviewers via computer-assisted interviews, which includes administration of an alcohol Breathalyzer test to assess alcohol use and collection of a urine sample to assess drug use. Interviews will be conducted at the treatment program (for those who remain in residential treatment) or at convenient locations for participants no longer in treatment. Baseline interview will occur prior to randomization, post-intervention interview will occur within 1-2 weeks of the last group session, and the follow-up interview will occur at an 8-months post-intervention completion window. Brain imaging for a subsample of participants will be completed at baseline and immediate post-intervention. * Number of intervention program class sessions attended will be collected for all enrolled participants. * Participant Satisfaction Surveys measuring acceptability, credibility, and perceived utility of the study arms will be administered to both groups at two class sessions. * Applied Mindfulness Practice Scale (AMPS) measuring the participant's application of mindfulness skills to address life challenges, will be administered to the MBRP-W participants at four class sessions as well as at follow-up. Mindfulness practice effort will also be assessed at these same four class sessions. * An in-treatment clinical record review of services will be collected weekly for the duration of residential treatment.