Substance use treatment; Outpatient; Outpatient methadone/buprenorphine or naltrexone treatment; Regular outpatient treatment; Methadone used in Treatment; Buprenorphine used in Treatment; Naltrexone used in Treatment; Does not treat alcohol use disorder; Buprenorphine maintenance; Buprenorphine maintenance for predetermined time; Federally-certified Opioid Treatment Program; Methadone maintenance; Methadone maintenance for predetermined time; Prescribes naltrexone; Relapse prevention with naltrexone; Methadone; Buprenorphine with naloxone; Buprenorphine without naloxone; Naltrexone (oral); Naltrexone (extended-release, injectable); Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Matrix Model; Relapse prevention; Substance use disorder counseling; Telemedicine/telehealth therapy; Private for-profit organization; State Substance use treatment agency; Commission on Accreditation of Rehabilitation Facilities (CARF); Federally Qualified Health Center; Drug Enforcement Agency (DEA); IHS/Tribal/Urban (ITU) funds; Medicare; Medicaid; Federal military insurance (e.g., TRICARE); Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Adult women; Pregnant/postpartum women; Adult men; Criminal justice (other than DUI/DWI)/Forensic clients; Clients with co-occurring mental and substance use disorders; Clients who have experienced trauma; Comprehensive substance use assessment; Outreach to persons in the community; Screening for tobacco use; Screening for substance use; Breathalyzer or blood alcohol testing; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; TB screening; Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Housing services; Employment counseling or training; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; 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; Social skills development; Transportation assistance