Project Summary/Abstract: The United States is experiencing an unprecedented opioid epidemic. Medications for opioid use disorder (MOUD), such as methadone, buprenorphine, and extended-release naltrexone, are the recommended standard of care. There are, however, many treatment barriers to MOUD adherence and retention that result in high MOUD discontinuation. This elevated MOUD dropout predicts poor health outcomes including increased opioid use/relapse, overdose, and death. To further compound the current opioid crisis, there are no established evidence-based interventions that specifically focus on improving MOUD adherence and retention, and typical strategies used by treatment providers are limited by being clinic- based. Thus, the goal of this study is to address this gap by developing an intervention that leverages the impact of two widely used existing recovery support services outside of usual treatment: peer recovery support services (PRSS) and recovery residences (RRs). The PRSS intervention will include the following components: coaching, mentoring, education, and other supports delivered by peers uniquely qualified by their lived experience with substance use disorder. RRs are another critical component of the intervention because they provide a supportive living environment for persons in recovery. The intervention will be tailored to specifically promote MOUD adherence. Peers will be embedded within the local provider community, provide assertive outreach between episodes of care, emphasize continuation in treatment, and emphasize return to care after treatment dropout and/or relapse. The potential synergistic benefits of combining PRSS and RRs to improve MOUD retention are considerable, and their impact will be investigated by including both components in the intervention developed in this proposed research study. The study involves three methodological phases linked to our specific aims that occur sequentially over 36 months. Phase 1 consists of preparation for the intervention implementation including building a network of RRs that will be recruitment sites in the pilot RCT, recruiting and training peer support specialists, conducting focus groups and interviews to gather stakeholder input, and developing PRSS approaches to promote MOUD retention. We will test the PRSS intervention in (n=5) individuals recruited from partnering RRs to prepare for Phase 2. Phase 2 consists of conducting the pilot RCT of the PRSS intervention by randomizing individuals (N=50) on MOUD who reside in partner RRs to either: a 24-week course of the PRSS intervention added to treatment as usual (TAU), or TAU without the PRSS intervention. Our primary outcome of the RCT is cumulative MOUD retention over the 24-weeks. Finally, phase 3 involves gathering additional qualitative input on PRSS intervention and conducting data analyses to inform the methodology for a follow-up R01 application. This research trajectory will support NIH’s mission by directly addres...