Substance use treatment; Outpatient; 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; Methadone maintenance for predetermined time; Methadone; Brief intervention; Contingency management/motivational incentives; Motivational interviewing; Substance use disorder counseling; Telemedicine/telehealth therapy; Private for-profit organization; State Substance use treatment agency; State department of health; The Joint Commission; 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; Adult women; Pregnant/postpartum women; Adult men; Seniors or older adults; Clients with co-occurring mental and substance use disorders; Clients with co-occurring pain and substance use disorders; Clients with HIV or AIDS; Comprehensive substance use assessment; Outreach to persons in the community; Complete medical history/physical exam; Screening for tobacco use; Screening for substance use; Screening for mental disorders; Professional interventionist/educational consultant; Breathalyzer or blood alcohol testing; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; HIV testing; TB screening; Metabolic syndrome monitoring; Testing for Hepatitis B (HBV); Testing for Hepatitis C (HCV); Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Assistance with obtaining social services; Employment counseling or training; Benzodiazepines Detoxification; Cocaine Detoxification; Methamphetamines detoxification; Opioids detoxification; Medication routinely used during detoxification; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking not permitted; Adults; Seniors; Young adults; Female; Male; Opioid use disorder clients only; Vaping not permitted; Case management service; Early intervention for HIV; Social skills development