Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; 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 buprenorphine; Prescribes naltrexone; Relapse prevention with naltrexone; Methadone; Buprenorphine with naloxone; Buprenorphine without naloxone; Naltrexone (oral); Naltrexone (extended-release, injectable); Brief intervention; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Telemedicine/telehealth therapy; Trauma-related counseling; Private for-profit organization; State Substance use treatment agency; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); Federal, or any government funding for substance use treatment programs; Medicare; Medicaid; Private health insurance; Cash or self-payment; Young adults; Adult women; Pregnant/postpartum women; Adult men; Seniors or older adults; Lesbian, gay, bisexual, transgender, or queer/questioning (LGBTQ); Veterans; Active duty military; Members of military families; Criminal justice (other than DUI/DWI)/Forensic clients; Clients with co-occurring mental and substance use disorders; Clients with co-occurring pain 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; 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; Housing services; Assistance with obtaining social services; Mentoring/peer support; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Smoking permitted in designated area; Adults; Children/adolescents; Seniors; Young adults; Female; Male; Opioid use disorder clients only; Spanish; Vaping permitted in designated area; Case management service; Mental health services