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 for predetermined time; Methadone; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Substance use disorder counseling; 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); Cash or self-payment; Drug or alcohol urine screening; STD testing; TB screening; Discharge Planning; HIV or AIDS education, counseling, or support; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Individual counseling; Smoking permitted without restriction; Adults; Young adults; Female; Male; Opioid use disorder clients only; Vaping permitted without restriction; Case management service