Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; 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; Buprenorphine maintenance for predetermined time; Federally-certified Opioid Treatment Program; Methadone maintenance; Methadone maintenance for predetermined time; Prescribes buprenorphine; Use methadone/buprenorphine for pain management or emergency dosing; Methadone; Buprenorphine with naloxone; Buprenorphine without naloxone; Anger management; Cognitive behavioral therapy; Contingency management/motivational incentives; Dialectical behavior therapy; Motivational interviewing; Matrix Model; Relapse prevention; Substance use disorder counseling; Telemedicine/telehealth therapy; Trauma-related counseling; Private non-profit organization; State Substance use treatment agency; State mental health department; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); Federally Qualified Health Center; Federal, or any government funding for substance use treatment programs; Medicare; Medicaid; Federal military insurance (e.g., TRICARE); Private health insurance; Cash or self-payment; Clients with HIV or AIDS; Comprehensive mental health assessment; Comprehensive substance use assessment; Interim services for clients; Screening for tobacco use; Screening for substance use; Screening for mental disorders; Professional interventionist/educational consultant; Breathalyzer or blood alcohol testing; Drug or alcohol urine screening; HIV testing; Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Housing services; HIV or AIDS education, counseling, or support; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Family counseling; Smoking not permitted; Adults; Young adults; Female; Male; Sign language services for the deaf and hard of hearing; Spanish; Early intervention for HIV; Mental health services