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 treat alcohol use disorder; Does not treat opioid use disorders; Private non-profit organization; State department of health; Medicare; Medicaid; Clients with co-occurring mental and substance use disorders; Comprehensive mental health assessment; Comprehensive substance use assessment; Screening for tobacco use; Screening for substance use; Screening for mental disorders; Discharge Planning; Outcome follow-up after discharge; Treatment for other addiction disorder; Substance use disorder education; Individual counseling; Group counseling; Smoking permitted in designated area; Adults; Young adults; Female; Male; Sign language services for the deaf and hard of hearing; Spanish; Vaping permitted in designated area; Case management service; Mental health services; Social skills development; Transportation assistance