The goal of this clinical trial is to examine the effects of mindfulness based relapse prevention on self-regulation overtime and drinking in daily life through the use of wearable heart rate sensors during mindfulness groups and answering assessment questions 3 times per day during the course of treatment. The main questions that it aims to answer are:

1. What changes in self-regulation as measured through heart rate variability are observed during a mindfulness intervention and how do those self-regulatory changes affect drinking after treatment?
2. How do changes in heart rate variability affect drinking, craving, and negative affectivity in daily life?

Participants will:

1. Answer questions related to their mood and drinking behaviors.
2. Wear their sensors during an 8-week treatment period with 1 group per week.
3. Answer questions 3 times a day during the treatment period. 4.) Return their sensors via a pre-stamped package and answer questions about their mood and drinking behaviors 3- and 6-months after the mindfulness groups end.

This study will assess the changes in self-regulation as measured through heart rate variability (HRV), that occur during the course of an 8-week mindfulness-based relapse prevention (MBRP) treatment. The investigators will use a single-group design to test the effects of MBRP on resting, reactivity, and recovery HRV. Additionally, the study will test whether changes in HRV that occur week over week during treatment can affect drinking behaviors in daily life. Individuals (n=120) who meet criteria for moderate to severe alcohol use disorder will be mailed small HRV sensors to be worn before, during, and after each MBRP group. Participants will answer questions about their functioning, alcohol use, addiction cycle domains, and mood at baseline, and at follow-up months 3 and 6.

MBRP groups will be delivered at the same time each week for 8 consecutive weeks, known as the treatment period. During the treatment period, participants will self-attach their sensors before each MBRP group, watch a brief presentation to collect resting HRV, complete their group, and watch a brief presentation after each group. During the treatment period, participants will also answer questions about their drinking, functioning, and mood 3 times a day.

Inclusion Criteria:

1. 18 years of age or older
2. Meet criteria for a moderate to severe alcohol use disorder within the previous 3-months.
3. Able to attend group meetings at the time listed on the recruitment materials.
4. Willing to wear a sensor for the 8-week intervention period and return the sensor after the immediate follow-up.
5. Have a phone/tablet/computer with internet access.
6. Be able to comprehend and consent to study requirements in English.
7. Have access to a valid U.S. mailing address for receiving the HRV sensors and reside in the United States.

Exclusion Criteria:

1. Current symptoms of psychosis or mania.
2. Have a substance use disorder requiring a higher level of care than outpatient treatment (e.g., severe alcohol use disorder requiring inpatient detoxification).
3. Have a history of pulmonary or cardiovascular disease that interferes with sensor data collection and HRV metrics (i.e., ectopic beats, arrythmia, congenital heart disease).

The investigators will comply with all NIAAA Data Archives policies established during the project period. This includes compliance with the NIAAA central data platform requirements and timelines developed through the NIAAA Data Share.

At the time of publication of the primary manuscript, or within 12 months of last patient assessment.

mplementation of the plan will follow the NIAAA Data Archive and Data Sharing Policy