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; Does not treat alcohol use disorder; Federally-certified Opioid Treatment Program; Methadone maintenance; Methadone; Brief intervention; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Relapse prevention; Substance use disorder counseling; 12-step facilitation; Private for-profit organization; State Substance use treatment agency; Cash or self-payment; Comprehensive substance use assessment; Outreach to persons in the community; Screening for substance use; Screening for mental disorders; Professional interventionist/educational consultant; Drug or alcohol urine screening; TB screening; Aftercare/continuing care; Discharge Planning; 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; Hepatitis education, counseling, or support; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Individual counseling; Smoking permitted in designated area; Adults; Young adults; Female; Male; Spanish; Case management service