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; Outpatient methadone/buprenorphine or naltrexone treatment; Regular outpatient treatment; Methadone used in Treatment; Buprenorphine used in Treatment; Does not treat alcohol use disorder; Buprenorphine maintenance; Federally-certified Opioid Treatment Program; Methadone maintenance; Methadone; Buprenorphine with naloxone; Buprenorphine without naloxone; Anger management; Brief intervention; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Matrix Model; Relapse prevention; Substance use disorder counseling; Trauma-related counseling; Telemedicine/telehealth therapy; 12-step facilitation; Private for-profit organization; State Substance use treatment agency; State department of health; Medicare; Medicaid; Cash or self-payment; 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; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; HIV testing; TB screening; Testing for Hepatitis C (HCV); Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Self-help groups; Housing services; Assistance with obtaining social services; Mentoring/peer support; Employment counseling or training; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Group counseling; Family counseling; Vocational training or educational support (for example, high school coursework, GED preparation, etc.) ; Smoking permitted in designated area; Adults; Young adults; Female; Male; Opioid use disorder clients only; Spanish; Vaping permitted in designated area; Case management service; Social skills development; Transportation assistance