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; Regular outpatient treatment; Does not use MAT for opioid use disorders; Medication for mental disorders; Private for-profit organization; State Substance use treatment agency; State mental health department; Commission on Accreditation of Rehabilitation Facilities (CARF); Medicare; Medicaid; Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Adolescents; 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 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; Outreach to persons in the community; Screening for substance use; Screening for mental disorders; Drug or alcohol urine screening; Aftercare/continuing care; Discharge Planning; Self-help groups; Assistance with obtaining social services; Mentoring/peer support; Treatment for other addiction disorder; Alcohol Detoxification; Benzodiazepines Detoxification; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking not permitted; Children/adolescents; Seniors; Female; Male; Mental health services; Social skills development