Anxiety disorders and the emergence of sex differences in major depression.

OBJECTIVE: To examine the role of anxiety disorders in the development of sex differences in the risk of major depression.
DESIGN: An epidemiologic study. PATIENTS: This study surveyed 1007 young adults, randomly selected from a large HMO in southeastern Michigan.
METHOD: The National Institute of Mental Health's Diagnostic Interview Schedule was administered to measure major depression and specific anxiety disorders (as per Diagnostic and Statistical Manual of Mental Disorders, third edition revised, guidelines). A composite variable--"any anxiety"--was used, and age of onset was defined as the age at which the earliest anxiety disorder began.
RESULTS: Prior anxiety signaled an increased risk for major depression in both sexes. Women were not more vulnerable than men to becoming depressed after an anxiety disorder. Prior anxiety disorders accounted for a considerable part of the sex differences in major depression. Controlling for prior substance use disorder did not alter the results.
CONCLUSION: Women's higher rates of anxiety disorders might play a role in their higher risk of depression. Substance use disorder is not men's counterpart of anxiety in terms of its potential role in the onset of depression. Future research should address the question of women's greater risk for anxiety disorders. Intervention trials to examine whether effective treatments of anxiety disorders might reduce the risk of depression would shed light on the mechanisms that link anxiety and depression.