Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; Residential/24-hour residential; Outpatient day treatment or partial hospitalization; Intensive outpatient treatment; Regular outpatient treatment; Long-term residential; Short-term residential; Does not use medication assisted treatment for alcohol use disorder; Does not use MAT for opioid use disorders; Medication for mental disorders; Anger management; Brief intervention; Cognitive behavioral therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Trauma-related counseling; Telemedicine/telehealth therapy; 12-step facilitation; Private for-profit organization; State Substance use treatment agency; State mental health department; State department of health; The Joint Commission; Federal military insurance (e.g., TRICARE); Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Adolescents; Clients with co-occurring mental and substance use disorders; Clients who have experienced sexual abuse; Clients who have experienced trauma; Comprehensive mental health assessment; Comprehensive substance use assessment; Outreach to persons in the community; Complete medical history/physical exam; Screening for tobacco use; Screening for substance use; Screening for mental disorders; Drug or alcohol urine screening; HIV testing; STD testing; TB screening; Aftercare/continuing care; Discharge Planning; Outcome follow-up after discharge; Self-help groups; Mentoring/peer support; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking not permitted; Adults; Children/adolescents; Young adults; Female; Male; Vaping not permitted; Case management service; Mental health services; Social skills development; Suicide prevention services