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; Brief intervention; Cognitive behavioral therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; 12-step facilitation; Private for-profit organization; State Substance use treatment agency; State department of health; The Joint Commission; SAMHSA certification for opioid treatment program (OTP); Drug Enforcement Agency (DEA); Medicare; Medicaid; Cash or self-payment; State-financed health insurance plan other than Medicaid; Adult women; Pregnant/postpartum women; Adult men; Complete medical history/physical exam; Screening for tobacco use; Screening for substance use; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; HIV testing; STD 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; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking permitted in designated area; Adults; Young adults; Female; Male; Opioid use disorder clients only; Sign language services for the deaf and hard of hearing; Vaping permitted in designated area; Case management service; Transportation assistance; Suicide prevention services