In this study, the enhanced treatment as usual intervention will encompass providing participants with information about diverse recovery activities (e.g., mutual help group meetings, exercise, job search, recovery coach meetings, etc.) and then to assign participants to complete a recovery activity of their choosing one two different days within one month after enrollment. Participants can do the same activity twice, or different activities on each of the two days assigned.

To assess completion of study assessments, we will check whether participants completed (including partial completions) (=1) or did not complete (=0) follow-up surveys at each assessment time point. Completion rates will be reported as the number and percent of participants completing them.

As part of assessing completion of study assessments, we will assess whether study participants completed the Timeline Follow-Back (TLFB) interview (=1) or not (=0) at each assessment time point. In the TLFB interviews, we will ask participants to go back through the last 30 days and report on specific recovery or substance use behaviors. For recovery supports, we will ask participants to tell us on which days they used medications for opioid use disorder or visited their local recovery community center. For substance use, we will ask participants about any non-prescribed opioid use, such as heroin or fentanyl, prescription opioids use without having a prescription for them, and any alcohol use. Completion of TLFB interviews will be reported as number and percent of participants completing them at each assessment point.

This 4-item self-report measure is derived directly from SAMHSA's (Substance Abuse and Mental Health Administration, 2012) working definition of recovery. The items are (1) "I have relationships and social networks that provide support, friendship, love, and hope"; (2) "I have a stable and safe place to live"; (3) "I have the independence, income and resources to participate in society"; and (4) "I have meaningful daily activities, such as a job, school, volunteerism, family care-taking, or creative endeavors." Each item is rated on a 3-point scale (0=no, not at all, 1=yes, somewhat, 2=yes). Scores on this measure will be presented as means of all 4 items (range 0-2), where higher scores indicate higher recovery capital.

In conceptualizing and evaluating peer support services, SAMHSA (Substance Abuse and Mental Health Services Administration) distinguishes between four types of support: emotional, informational, instrumental, and affiliation support. To capture to what degree study participants experienced receiving these types of support, our study team created a 4-item self-report scale: (1) "I have experienced caring.";(2) "I have gained knowledge to help me reach my goals (e.g., wellness seminar, job training, parenting class, etc.)"; (3) "I have received concrete assistance to help me accomplish tasks (e.g., childcare, transportation, help accessing community health and social services)"; and (4) "I have felt a sense of belonging through shared activities with others." Each item is rated on a 4-point scale (3="Yes, a lot", 2="Yes, somewhat", 1="No, not really", 0="No, not at all"). Scores are averaged (range 0-3), where higher scores indicate higher levels of support.

The Brief Assessment of Recovery Capital (BARC-10) is a 10-item self-report measure that is a short form of the 50-item Assessment of Recovery Capital (ARC) scale. Participants are asked to respond to each statement using a 6-point Likert scale ranging from 1 (="strongly disagree") to 6 (= "strongly agree"). The participant's response is then recorded and entered as a binary response option (agree = 1 / disagree = 0). The total score is the sum of all items that can range from 0 to 10, where higher scores indicate greater levels of recovery capital.

Participation in Recovery Support Services is a 3-item self-report questionnaire created by the investigators that assesses the participant's engagement (yes/no; if yes, how many days in the past 30 days) with a variety of recovery support services including mutual help organizations (e.g., Alcoholics Anonymous, Celebrate Recovery) and community recovery support services (e.g., recovery housing, recovery community centers). Answers will be summarized descriptively (% yes for listed mutual help organizations or recovery support services).

The Generalized Anxiety Disorder Screener (GAD-7) is a 7-item self-report scale that is used to assess the severity of generalized anxiety within participants over the previous 2-week period (e.g., "Feeling nervous, anxious or on edge."). Participants answer each item on a 4-point Likert scale ranging from 0 (= not at all) to 3 (= nearly every day). Scores are summed to a total score that can range from 0 to 21, where higher scores indicate more severe anxiety.

The Patient Health Questionnaire for Depression (PHQ-8) is an 8-item self-report measure used to assess participants' depression severity over the prior 2-week period (e.g., "Feeling down, depressed, or hopeless"). Participants answer each item on a 4-point Likert scale ranging from 0 = "Not at all (0 to 1 day)" to 3 = "Nearly every day (12-14 days)." Items are summed to form a total score that can range from 0 to 24, where higher scores indicate greater depression severity.