The preferred term is substance use disorder. When referring to opioids, see the Opioid Use Disorder (OUD) definition below and text box discussing the difference between “tolerance,” “dependence,” and “addiction.”

A problematic pattern of opioid use that causes significant impairment or distress. A diagnosis is based on specific criteria such as unsuccessful efforts to cut down or control use, or use resulting in social problems and a failure to fulfill obligations at work, school, or home, among other criteria. Opioid use disorder is preferred over other terms with similar definitions, “opioid abuse or dependence” or “opioid addiction.”

Reduced response to a drug with repeated use.