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; Naltrexone 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; Prescribes naltrexone; Methadone; Buprenorphine with naloxone; Buprenorphine without naloxone; Buprenorphine (extended-release, injectable); Naltrexone (oral); Naltrexone (extended-release, injectable); Medication for mental disorders; Cognitive behavioral therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Telemedicine/telehealth therapy; Private non-profit organization; State Substance use treatment agency; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); SAMHSA certification for opioid treatment program (OTP); Federal, or any government funding for substance use treatment programs; Medicare; Medicaid; Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; SAMHSA funding/block grants; Sliding fee scale (fee is based on income and other factors); Pregnant/postpartum women; Veterans; Criminal justice (other than DUI/DWI)/Forensic clients; Clients with co-occurring mental and substance use disorders; Clients who have experienced trauma; Comprehensive substance use assessment; Screening for substance use; Screening for mental disorders; Breathalyzer or blood alcohol testing; Drug or alcohol urine screening; HIV testing; TB screening; Discharge Planning; Naloxone and overdose education; Housing services; Assistance with obtaining social services; Mentoring/peer support; Employment counseling or training; HIV or AIDS education, counseling, or support; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Smoking not permitted; Adults; Young adults; Female; Male; Spanish; Sign language services for the deaf and hard of hearing; Vaping not permitted; Case management service; Mental health services; Social skills development