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; Brief intervention; Cognitive behavioral therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Trauma-related counseling; Telemedicine/telehealth therapy; Private for-profit organization; State Substance use treatment agency; State mental health department; State department of health; The Joint Commission; Medicaid; Federal military insurance (e.g., TRICARE); Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Adult women; Adult men; Clients with co-occurring mental and substance use disorders; Comprehensive mental health assessment; Comprehensive substance use assessment; Interim services for clients; Outreach to persons in the community; Screening for tobacco use; Screening for substance use; Screening for mental disorders; Breathalyzer or blood alcohol testing; Drug or alcohol urine screening; Aftercare/continuing care; Discharge Planning; Outcome follow-up after discharge; Assistance with obtaining social services; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking permitted in designated area; Adults; Young adults; Female; Male; Vaping permitted in designated area; Case management service; Mental health services; Social skills development