Comorbidity of depressive and anxiety disorders for older Americans in the national comorbidity survey-replication.

OBJECTIVE: To identify age differences in the 12-month and lifetime comorbidity of depressive and anxiety disorders for adults (18-64 years) compared with older adults (65 years and older) in a nationally representative sample of community-dwelling adults in the United States.
DESIGN: Cross-sectional epidemiologic study, using data from the National Comorbidity Survey-Replication public use dataset.
SETTING: Community-based epidemiologic survey. PARTICIPANTS: Representative national sample of community-dwelling adults in the United States. MEASUREMENTS: The World Health Organization Composite International Diagnostic Interview was used to assess Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition psychiatric disorders.
RESULTS: More than half of respondents with a 12-month major depressive disorder (MDD) had a comorbid anxiety disorder or dysthymia (18-64 years = 60.6%; 65 years and older = 51.8%). High rates of MDD were also found for those with anxiety disorders across both age groups, highest in the 18-64 years group for generalized anxiety disorder (28.5%) and highest in the 65 years and older group for panic disorder (36.7%). Age group did not predict 12-month diagnosis of a comorbid anxiety disorder among those with a depressive disorder in multivariate logistic regression. Onset of anxiety disorders preceded onset of depressive disorders for most older adults (77.6%).
CONCLUSIONS: Depressive and anxiety disorders frequently cooccurred in this representative sample of community-dwelling adults. Older adults experienced comorbidity to a similar extent as younger adults, suggesting high rates of comorbidity across the lifespan.