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; Does not use medication assisted treatment for alcohol use disorder; Does not treat opioid use disorders; Cognitive behavioral therapy; Contingency management/motivational incentives; Dialectical behavior therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Trauma-related counseling; Private for-profit organization; State Substance use treatment agency; Medicaid; Private health insurance; Cash or self-payment; Adolescents; Young adults; Adult women; Adult men; Seniors or older adults; Lesbian, gay, bisexual, transgender, or queer/questioning (LGBTQ); Veterans; 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; Screening for substance use; Screening for mental disorders; Drug or alcohol urine screening; Aftercare/continuing care; Discharge Planning; HIV or AIDS education, counseling, or support; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Marital/couples counseling; Smoking not permitted; Seniors; Female; Male; Specially designed program for DUI/DWI clients; Mental health services