Multiple DSM-5 substance use disorders: A national study of US adults.

Assessment, diagnosis, and treatment often focus on individual substance-specific SUDs rather than multiple SUDs, despite evidence for substantial rates of polysubstance use in clinical and epidemiological studies. There are notable differences in the prevalence of multiple SUDs between alcohol use disorders and other nonalcohol SUDs that have important clinical implications; for example, multiple SUDs are more persistent than individual SUDs. These findings suggest that clinical assessment and diagnosis should screen for multiple SUDs, especially among adults with nonalcohol DSM-5 SUDs.