Substance Use and Co-Occurring Mental Disorders (National Institutes of Health)

Substance use disorder (SUD) is a treatable mental disorder that affects a person’s brain and behavior, leading to their inability to control their use of substances like legal or illegal drugs, alcohol, or medications. Symptoms can be moderate to severe, with addiction being the most severe form of SUD.

People with a SUD may also have other mental health disorders, and people with mental health disorders may also struggle with substance use.