Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; 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; Telemedicine/telehealth therapy; Trauma-related counseling; Private for-profit organization; Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Young adults; Clients who have experienced trauma; Comprehensive mental health assessment; Comprehensive substance use assessment; Screening for substance use; Screening for mental disorders; Professional interventionist/educational consultant; Aftercare/continuing care; Recovery coach; Treatment for other addiction disorder; Substance use disorder education; Individual counseling; Marital/couples counseling; Smoking permitted without restriction; Children/adolescents; Female; Male; Vaping permitted without restriction; Mental health services