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; Naltrexone used in Treatment; No formal relationship with prescribing entity; Does not treat alcohol use disorder; Accepts clients using MAT but prescribed elsewhere; Medication for mental disorders; Cognitive behavioral therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Trauma-related counseling; Private non-profit organization; State Substance use treatment agency; State mental health department; State department of health; The Joint Commission; Federal, or any government funding for substance use treatment programs; Medicaid; Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Sliding fee scale (fee is based on income and other factors); 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; Professional interventionist/educational consultant; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Housing services; Assistance with obtaining social services; Mentoring/peer support; Treatment for gambling disorder; Treatment for other addiction disorder; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking permitted in designated area; Female; Male; Sign language services for the deaf and hard of hearing; Vaping permitted in designated area; Case management service; Domestic violence services, including family or partner; Mental health services; Social skills development; Suicide prevention services