Substance use treatment; Detoxification; Outpatient; Outpatient detoxification; 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 detoxification; Methadone maintenance; Methadone maintenance for predetermined time; Methadone; Relapse prevention; Substance use disorder counseling; Private for-profit organization; State Substance use treatment agency; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); SAMHSA certification for opioid treatment program (OTP); Drug Enforcement Agency (DEA); Cash or self-payment; Comprehensive substance use assessment; Complete medical history/physical exam; Screening for substance use; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; HIV testing; STD testing; TB screening; Metabolic syndrome monitoring; Testing for Hepatitis B (HBV); Testing for Hepatitis C (HCV); Aftercare/continuing care; Discharge Planning; Outcome follow-up after discharge; Housing services; Assistance with obtaining social services; Employment counseling or training; Opioids detoxification; Medication routinely used during detoxification; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; Substance use disorder education; Individual counseling; Group counseling; Smoking permitted without restriction; Adults; Young adults; Female; Male; Opioid use disorder clients only; Vaping permitted without restriction; Case management service; Early intervention for HIV; Social skills development