Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; Intensive outpatient treatment; Outpatient methadone/buprenorphine or naltrexone treatment; Regular outpatient treatment; Methadone used in Treatment; Buprenorphine 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 buprenorphine; Methadone; Buprenorphine with naloxone; Medication for mental disorders; Anger management; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Matrix Model; Relapse prevention; Substance use disorder counseling; Telemedicine/telehealth therapy; Trauma-related counseling; 12-step facilitation; 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); Medicare; Medicaid; Private health insurance; State-financed health insurance plan other than Medicaid; Young adults; Adult women; Pregnant/postpartum women; Adult men; Seniors or older adults; Clients with co-occurring mental and substance use disorders; Clients with HIV or AIDS; Clients who have experienced sexual abuse; Clients who have experienced intimate partner violence, domestic violence; Clients who have experienced trauma; Comprehensive mental health assessment; 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; Screening for mental disorders; Breathalyzer or blood alcohol testing; Drug or alcohol urine screening; HIV testing; STD testing; TB screening; Testing for Hepatitis B (HBV); Testing for Hepatitis C (HCV); Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Self-help groups; Housing services; Assistance with obtaining social services; Mentoring/peer support; Employment counseling or training; Treatment for gambling disorder; Treatment for other addiction disorder; 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 permitted in designated area; Adults; Seniors; Young adults; Female; Male; Spanish; Other languages (excluding Spanish); Greek; Russian; Vaping permitted in designated area; Case management service; Domestic violence services, including family or partner; Early intervention for HIV; Mental health services; Social skills development; Transportation assistance; Suicide prevention services