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; Buprenorphine used in Treatment; Naltrexone used in Treatment; No formal relationship with prescribing entity; Does not treat alcohol use disorder; Buprenorphine maintenance; Buprenorphine maintenance for predetermined time; Prescribes buprenorphine; Prescribes naltrexone; Relapse prevention with naltrexone; Accepts clients using MAT but prescribed elsewhere; Buprenorphine with naloxone; Naltrexone (oral); Clonidine; Medication for mental disorders; Non-nicotine smoking/tobacco cessation; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Trauma-related counseling; Telemedicine/telehealth therapy; Private for-profit organization; Healthcare Facilities Accreditation Program (HFAP); SAMHSA certification for opioid treatment program (OTP); Medicare; Medicaid; Federal military insurance (e.g., TRICARE); Private health insurance; Cash or self-payment; State-financed health insurance plan other than Medicaid; Young adults; Adult women; Adult men; Seniors or older adults; Clients with co-occurring mental and substance use disorders; Clients with co-occurring pain and substance use disorders; Comprehensive substance use assessment; Screening for tobacco use; Screening for substance use; Screening for mental disorders; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; Naloxone and overdose education; Treatment for gambling disorder; Treatment for other addiction disorder; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Group counseling; Smoking not permitted; Adults; Seniors; Young adults; Female; Male; Sign language services for the deaf and hard of hearing; Vaping not permitted; Mental health services