Substance use treatment; Outpatient; Outpatient methadone/buprenorphine or naltrexone treatment; Regular outpatient treatment; Methadone used in Treatment; Buprenorphine used in Treatment; Federally-certified Opioid Treatment Program; Methadone; Buprenorphine with naloxone; Buprenorphine without naloxone; Private for-profit organization; State Substance use treatment agency; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); Federal, or any government funding for substance use treatment programs; Medicaid; Private health insurance; Cash or self-payment; Pregnant/postpartum women; Comprehensive substance use assessment; Interim services for clients; Outreach to persons in the community; Screening for substance use; Breathalyzer or blood alcohol testing; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; HIV testing; STD testing; TB screening; Testing for Hepatitis B (HBV); Testing for Hepatitis C (HCV); Aftercare/continuing care; Discharge Planning; Outcome follow-up after discharge; Substance use disorder education; Individual counseling; Family counseling; Marital/couples counseling; Smoking permitted without restriction; Adults; Young adults; Female; Male; Opioid use disorder clients only; Spanish; Sign language services for the deaf and hard of hearing; Case management service