Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; Outpatient day treatment or partial hospitalization; Intensive outpatient treatment; Regular outpatient treatment; No formal relationship with prescribing entity; Accepts clients using medication assisted treatment for alcohol use disorder but prescribed elsewhere; No formal relationship with prescribing entity; Accepts clients using MAT but prescribed elsewhere; Anger management; Brief intervention; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Telemedicine/telehealth therapy; Trauma-related counseling; 12-step facilitation; Private non-profit organization; State Substance use treatment agency; State mental health department; State department of health; Federally Qualified Health Center; Private health insurance; Cash or self-payment; Sliding fee scale (fee is based on income and other factors); Adolescents; Young adults; Adult women; Adult men; Clients with co-occurring mental and substance use disorders; Clients with co-occurring pain and substance use disorders; Clients who have experienced sexual abuse; Clients who have experienced trauma; Comprehensive mental health assessment; Comprehensive substance use assessment; Interim services for clients; Outreach to persons in the community; Screening for substance use; Screening for mental disorders; Professional interventionist/educational consultant; Drug or alcohol urine screening; Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Self-help groups; Mentoring/peer support; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking not permitted; Children/adolescents; Female; Male; Vaping not permitted; Case management service; Mental health services; Social skills development; Suicide prevention services