Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; Regular outpatient treatment; Does not treat alcohol use disorder; Does not treat opioid use disorders; Medication for mental disorders; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Trauma-related counseling; Local, county, or community government; State Substance use treatment agency; State mental health department; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); Federally Qualified Health Center; Federal, or any government funding for substance use treatment programs; Medicaid; Cash or self-payment; Sliding fee scale (fee is based on income and other factors); Adolescents; Young adults; Lesbian, gay, bisexual, transgender, or queer/questioning (LGBTQ); 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 tobacco use; Screening for substance use; Screening for mental disorders; Professional interventionist/educational consultant; Drug or alcohol urine screening; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Assistance with obtaining social services; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Group counseling; Family counseling; Smoking not permitted; Adults; Children/adolescents; Young adults; Female; Male; Spanish; Vaping not permitted; Case management service; Mental health services; Social skills development; Suicide prevention services