Reference

Addiction treatment glossary: Key terms defined

Published December 5, 2024 · 8 min read · Updated April 2026

Reviewed for accuracy by licensed clinical professionals.

Understanding addiction terminology helps you navigate treatment conversations, insurance processes, and recovery community.

Clinical terms

AUD: Alcohol Use Disorder. SUD: Substance Use Disorder. MAT: Medication-Assisted Treatment. OUD: Opioid Use Disorder. DSM-5: Diagnostic manual used for diagnosis. ASAM: American Society of Addiction Medicine.

Treatment terms

Detox: Medical withdrawal management. Residential: 24/7 inpatient treatment. PHP: Partial Hospitalization Program. IOP: Intensive Outpatient Program. OP: Outpatient. Sober living: Substance-free transitional housing. Aftercare: Post-treatment continuing care.

Recovery terms

Sobriety: Abstinence from substances. Clean time: Duration of abstinence. Sponsor: Recovery mentor in 12-step programs. Step work: Working through the 12 steps. Pink cloud: Early recovery euphoria. HALT: Hungry, Angry, Lonely, Tired.

Insurance terms

Prior authorization: Pre-approval from insurance. Utilization review: Insurance review of treatment necessity. Medical necessity: Clinical criteria for coverage. Parity: Equal coverage for mental health and medical care. Appeal: Challenging an insurance denial.

Authoritative sources

This article references guidelines from: SAMHSA · NIDA · ASAM

Frequently asked questions

What does MAT stand for?

Medication-Assisted Treatment (now often called MOUD: Medications for Opioid Use Disorder).

What is the difference between IOP and PHP?

IOP: 3-4 hours, 3-5 days/week. PHP: 6-8 hours, 5 days/week. PHP is more intensive.

What does ASAM stand for?

American Society of Addiction Medicine. Their criteria determine appropriate treatment level.

Disclaimer: Informational only. Not medical advice. SAMHSA: 1-800-662-4357.