Substance use treatment; Outpatient; Intensive outpatient treatment; Outpatient methadone/buprenorphine or naltrexone treatment; Regular outpatient treatment; Methadone used in Treatment; Naltrexone used in Treatment; Does not treat alcohol use disorder; Federally-certified Opioid Treatment Program; Methadone maintenance; Methadone maintenance for predetermined time; Relapse prevention with naltrexone; Methadone; Naltrexone (extended-release, injectable); Cognitive behavioral therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Private for-profit organization; State Substance use treatment agency; Commission on Accreditation of Rehabilitation Facilities (CARF); SAMHSA certification for opioid treatment program (OTP); Drug Enforcement Agency (DEA); Medicare; Medicaid; Cash or self-payment; Adult women; Pregnant/postpartum women; Adult men; Criminal justice (other than DUI/DWI)/Forensic clients; Comprehensive substance use assessment; Interim services for clients; Outreach to persons in the community; Complete medical history/physical exam; Screening for substance use; Breathalyzer or blood alcohol testing; Drug or alcohol urine screening; STD testing; TB screening; Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Smoking permitted without restriction; Adults; Young adults; Female; Male; Spanish; Vaping permitted without restriction; Case management service; Early intervention for HIV