A longitudinal study of the order of onset of alcohol dependence and major depression.

Alcohol dependence and major depression commonly occur together; however, few studies have assessed prospectively the magnitude of the risk that one disorder imparts on the subsequent occurrence of the other. We used data from the first two waves of the Epidemiologic Catchment Area community survey (n=14480) to estimate the odds of either major depression or alcohol dependence being followed by the other disorder after 1 year of follow-up. The odds of developing major depression associated with low, medium, and high levels of alcoholic symptoms at baseline were 1.66, 3.98, and 4.32 for females (P<0.001), and 1.19, 2.49, and 2.12 for males (P=0.026). Conversely, odds ratios indicating the 1-year follow-up risk of incident alcohol dependence within low, medium, and high categories of baseline depressive symptomatology were 2.75, 3.52, and 7.88 for females (P<0.001) and 1.50, 1.41, and 1.05 for males (P=0.091). Individuals with alcohol dependence appeared more likely to meet lifetime diagnostic criteria for both disorders after 1 year than individuals with depression. These results suggest that both alcohol dependence and major depression pose a significant risk for the development of the other disorder at 1 year.