Substance use treatment; Outpatient; Outpatient methadone/buprenorphine or naltrexone treatment; Regular outpatient treatment; Methadone used in Treatment; Buprenorphine used in Treatment; Does not treat alcohol use disorder; Buprenorphine maintenance; Federally-certified Opioid Treatment Program; Methadone maintenance; Methadone; Buprenorphine with naloxone; Buprenorphine without naloxone; Cognitive behavioral therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Private for-profit organization; State Substance use treatment agency; State mental health department; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); Federal, or any government funding for substance use treatment programs; Medicare; Medicaid; Cash or self-payment; State-financed health insurance plan other than Medicaid; Pregnant/postpartum women; Complete medical history/physical exam; Screening for substance use; Breathalyzer or blood alcohol testing; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; HIV testing; STD testing; TB screening; Testing for Hepatitis B (HBV); Testing for Hepatitis C (HCV); Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Self-help groups; Housing services; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Group counseling; Smoking not permitted; Adults; Young adults; Female; Male; Opioid use disorder clients only; Spanish; Vaping not permitted; Case management service; Integrated primary care services; Suicide prevention services