RecruitingBehavioural interventionSocial Functioning in Opioid Use DisorderProblems with social functioning are core to opioid use disorder (OUD), though specific, modifiable social functioning targets and how they relate to OUD treatment outcomes are poorly understood. This study will utilize both data from both patients with OUD and their concerned significant other (CSO) to examine associations between specific social functioning metrics and OUD treatment outcomes. Findings from this study will inform future precision-medicine approaches for people with OUD, a population in significant need of enhanced treatment approaches to combat opioid morbidity and mortality.