Major depression in 6050 former drinkers: association with past alcohol dependence.

BACKGROUND: The association between alcoholism and major depression in the general population has been explained as misdiagnosed alcohol intoxication and withdrawal effects mistaken for depressive syndromes. To investigate whether this could account for the entire relationship, the association of past alcohol dependence with current major depression (ie, nonoverlapping time frames) was investigated in individuals who no longer drink or who drink very little. We conducted the study using data from the National Longitudinal Alcohol Epidemiologic Survey, a representative sample.
METHODS: Former drinkers who did not use drugs or smoke in the past year (n = 6050) were divided into those with and without past DSM-IV alcohol dependence. These 2 groups were compared for the presence of current (last 12 months) DSM-IV major depression. The association between prior alcohol dependence and current major depression was tested with linear logistic regression, controlling for other variables.
RESULTS: Prior alcohol dependence increased the risk of current major depressive disorder more than 4-fold. This relationship was not attenuated by control variables. The majority of subjects with major depression last used substances 2 or more years prior to the interview, which eliminates acute intoxication or withdrawal effects as an explanation of their depressions.
CONCLUSIONS: The strong, specific association between prior alcohol dependence and current or recent major depression in a nationally representative sample of former drinkers indicates that the association is not entirely an artifact of misdiagnosed intoxication and withdrawal effects. A better understanding of the nature of the relationship between the 2 disorders should be sought and will have important public health significance.