PURPOSE: To examine the prevalence and correlates of mental disorder comorbidity in the adult U.S. household population.
METHODS: Data are from a nationally representative sample of noninstitutionalized, civilian adults aged 18 years or older (n = 5653) who participated in the 2008-2012 Mental Health Surveillance Study. Mental disorders, including substance use disorders, were assessed by clinical interviewers using a semistructured diagnostic instrument. Analyses examined co-occurrence of mental disorders and associations with sociodemographic, functional impairment, and treatment correlates.
RESULTS: Approximately one-third of adults (31.1%, or more than 15 million) with a past-year mental disorder had a co-occurring mental disorder. Correlates of comorbidity in adjusted models included being of young age, being of non-Hispanic white race/ethnicity, having low family income, and living in a large metropolitan area. Adults with comorbid mental disorders had lower mean levels of functioning and were more likely to report past-year treatment than adults with a single disorder; they also had higher estimates of past-year perceived unmet need for care (21.7% vs. 11.6%, P < .01).
CONCLUSIONS: About one in three adults with a mental disorder have a co-occurring mental disorder. Elucidating factors associated with co-occurrence may lend clues to shared etiologies, help improve prevention efforts, facilitate early identification, and improve treatment regimens.