Inclusion Criteria:  18 years of age and older Opioid-positive urine sample at admission visit (excluding individuals receiving Naltrexone). Current opioid use disorder per Diagnostic Statistical Manual (DSM)-5 Currently in treatment for opioid use disorder  Exclusion Criteria:  Being pregnant or breastfeeding, or may become pregnant during the trial History of psychosis or mania or other serious psychiatric disorders assessed by the Mini International Neuropsychiatric Interview Past 30-day suicidal behavior assessed by the Columbia Suicide Severity Rating Scale Have circumstances that would interfere with study participation (e.g., impending jail). Positive for illicit substances except opioids and cannabis Current substance use disorder other than opioid or nicotine Current intoxication