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; Does not use medication assisted treatment for alcohol use disorder; Does not use MAT for opioid use disorders; Medication for mental disorders; Cognitive behavioral therapy; Substance use disorder counseling; Telemedicine/telehealth therapy; Trauma-related counseling; Private for-profit organization; State Substance use treatment agency; State mental health department; State department of health; The Joint Commission; Private health insurance; Cash or self-payment; Adolescents; Clients with co-occurring mental and substance use disorders; Clients who have experienced trauma; Comprehensive mental health assessment; Comprehensive substance use assessment; Screening for substance use; Screening for mental disorders; Breathalyzer or blood alcohol testing; Drug or alcohol urine screening; Discharge Planning; Outcome follow-up after discharge; Self-help groups; Mentoring/peer support; Treatment for other addiction disorder; HIV or AIDS education, counseling, or support; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Vocational training or educational support (for example, high school coursework, GED preparation, etc.) ; Smoking not permitted; Children/adolescents; Female; Male; Vaping not permitted; Case management service; Mental health services; Social skills development; Suicide prevention services