Substance use treatment; Detoxification; Outpatient; Outpatient detoxification; Intensive outpatient treatment; Outpatient methadone/buprenorphine or naltrexone treatment; Regular outpatient treatment; Methadone used in Treatment; Does not treat alcohol use disorder; Federally-certified Opioid Treatment Program; Methadone maintenance; Disulfiram; Methadone; Brief intervention; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Matrix Model; Relapse prevention; Substance use disorder counseling; Trauma-related counseling; Telemedicine/telehealth therapy; 12-step facilitation; Private for-profit organization; State Substance use treatment agency; State mental health department; Commission on Accreditation of Rehabilitation Facilities (CARF); SAMHSA certification for opioid treatment program (OTP); Drug Enforcement Agency (DEA); Medicare; Medicaid; Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Young adults; Adult women; Adult men; Clients with co-occurring mental and substance use disorders; Comprehensive substance use assessment; Interim services for clients; Outreach to persons in the community; Complete medical history/physical exam; Screening for tobacco use; Screening for substance use; Breathalyzer or blood alcohol testing; Drug or alcohol urine screening; STD testing; TB screening; Aftercare/continuing care; Discharge Planning; Outcome follow-up after discharge; Self-help groups; Housing services; Opioids detoxification; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking not permitted; Adults; Young adults; Female; Male; Opioid use disorder clients only; Vaping not permitted; Case management service; Domestic violence services, including family or partner; Social skills development; Transportation assistance