Substance use treatment; Outpatient; Outpatient methadone/buprenorphine or naltrexone treatment; Methadone used in Treatment; Does not treat alcohol use disorder; Federally-certified Opioid Treatment Program; Methadone maintenance; Methadone maintenance for predetermined time; Methadone; Anger management; Brief intervention; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Telemedicine/telehealth therapy; Private for-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); Drug Enforcement Agency (DEA); Federal, or any government funding for substance use treatment programs; Medicare; Medicaid; Cash or self-payment; Adult women; Adult men; Clients with co-occurring pain and substance use disorders; Comprehensive substance use assessment; Complete medical history/physical exam; Screening for tobacco use; Screening for substance use; Professional interventionist/educational consultant; Breathalyzer or blood alcohol testing; Drug or alcohol urine screening; TB screening; 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; HIV or AIDS education, counseling, or support; Substance use disorder education; Individual counseling; Group counseling; Smoking permitted in designated area; Adults; Young adults; Female; Male; Opioid use disorder clients only; Vaping permitted in designated area; Case management service; Transportation assistance