Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; 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; Medication for mental disorders; Anger management; 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; Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Adolescents; Young adults; Clients with co-occurring mental and substance use disorders; Comprehensive substance use assessment; Screening for tobacco use; Screening for substance use; Screening for mental disorders; Drug or alcohol urine screening; Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Mentoring/peer support; Employment counseling or training; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Vocational training or educational support (for example, high school coursework, GED preparation, etc.) ; Smoking permitted in designated area; Female; Male; Vaping permitted in designated area; Case management service; Mental health services; Social skills development; Suicide prevention services; Adults; Children/adolescents