This study seeks primarily to test, in a two-arm randomized controlled trial (RCT), the feasibility, acceptability, and preliminary efficacy of CoMBAT OUD, an intervention that integrates Behavioral Activation (BA) and substance abuse and health navigation counseling for individuals who are receiving medications for opioid use disorder (i.e., methadone; suboxone) to help them improve engagement in care and opioid use treatment outcomes. Participants will be randomized 1:1 to two arms: (1) the CoMBAT intervention (2 sessions of substance abuse and health navigation counseling + 8 sessions of BA counseling); or the (3) the standard of care (SOC) comparison condition, including two equivalent substance abuse and health navigation counseling. Participants will be followed for 6 months post-randomization, with assessments at months 3 and 6.

Opioid use disorder (OUD) is a chronic, relapsing disease and a major source of morbidity and mortality in the United States. Medications for opioid use disorder (i.e., methadone; buprenorphine) have been shown to reduce opioid use in diverse populations; however, long-term use of these medications and engagement in care are often suboptimal. Depression has been shown to contribute to medication discontinuation and care disengagement. Behavioral activation (BA) therapy is an evidence-based, behavioral treatment that has been shown to be effective in treating comorbid depression and substance use in diverse populations with smoking, alcohol, stimulant, and poly-substance use disorder. BA utilizes therapeutic techniques that help patients gradually increase goal-directed, potentially rewarding and pleasurable activities while decreasing the intensity and frequency of adverse events and consequences in order to improve mood. Given that BA utilizes strategies that can support individuals in alleviating depression and build the capacity to navigate life challenges, pairing BA with medications for OUD could help to ensure continued engagement in care and improve OUD treatment outcomes.

This study, therefore, seeks to determine the feasibility of study procedures, enhance participant acceptability, and demonstrate preliminary efficacy of the CoMBAT (Combined Medication and Behavioral Activation Treatment) intervention. The investigators will enroll individuals currently being treated with methadone or buprenorphine for OUD in a pilot randomized controlled trial (RCT) of the CoMBAT intervention. Prior to randomization, participants will receive 2 health navigation and standard substance abuse counseling sessions. Participants will then be equally randomized to either: 1) the 8-session CoMBAT intervention; or 2) standard of care. The primary outcome is engagement in care. Secondary outcomes include self-reported days of opioid use and opioid-positive urinalysis. Intervention feasibility and acceptability will also be assessed. Participants will complete major assessment visits (survey and toxicology testing) at baseline and 3- and 6-months post-randomization.

Inclusion Criteria:

• Age 18 years or older
• Initiated medications for opioid use >= 30 day prior to screening
• Current depressive symptoms
• Plans to stay in Rhode Island or Massachusetts for at least 6-months
• Able to read, speak, and understand English
• Willing and able to provide informed consent

Exclusion Criteria:

• Does not plan to continue taking medications for opioid use disorder
• Unable to provide informed consent due to severe mental or physical illness, or substance intoxication at the time of interview
• Discovery of active suicidal ideation at the time of interview
• In the second or third trimester of pregnancy

Raw data for additional analysis will be available to outside individuals through contacting the Principal Investigator (PI) at two different times. The first will be after all of the baseline data is collected. The PI will institute a concept plan process where internal study staff first have the availability to write papers or give presentations on particular topics. After this, if outside individuals wish to analyze the data, the PI will welcome this collaboration. A similar process will happen for outcome data; however, this will not be possible until the publication and release of the outcome paper(s). The PI will allow access for pooled data analysis projects, or projects for outside individuals. Information regarding the availability of data for analysis will be listed on the PIs' web page. Contact information for the PI will be listed in all manuscripts and publications as another means to access data.

The first time point at which outside investigators may request IPD will be after all of the baseline data has been collected and internal study staff have been offered the availability to write papers or give presentations on particular topics. A similar process will take place for outcome data following publication and release of the outcome paper(s). The PI will store the data indefinitely.

Raw data for additional analysis will be available to outside individuals by contacting the Principal Investigator (PI). The PI will institute a concept plan process where internal study staff first have the availability to write papers or give presentations on particular topics. After this, if outside individuals wish to analyze data, the PI will welcome this collaboration. The PI will allow access for pooled data analysis projects, or projects for outside individuals. Information regarding the availability of data for analysis will be listed on the PI's web page (see below).