Examination of a possible J-shaped relationship between alcohol consumption and internalizing disorders in a longitudinal birth cohort

Background: Many studies have reported a J-shaped relationship between alcohol use and affective or anxiety symptoms, with abstainers experiencing more severe symptoms than moderate drinkers. It is less clear whether this relationship is also present for the risk of syndromal internalizing disorders such as depression or anxiety disorders. Methods: A New Zealand longitudinal birth cohort study (n = 1265). Participants were interviewed at ages 18, 21, 25, 30 and 35 years. Alcohol consumption level and the presence of internalizing disorders (major depression; anxiety disorder) for the previous 12 months were determined at each time point. The association between drinking status and major depression and anxiety disorders at ages 18, 21, 25, 30 and 35 years was investigated via Generalized Estimating Equation modelling. Results: There was little evidence of a statistically significant (p < .05) association between alcohol consumption levels and either: (a) major depression; or (b) anxiety disorder; across the period 18-35 years. Inspection of the annual data showed considerable fluctuation in rates of disorder across alcohol consumption categories. Conclusion: In young adults there was little evidence of a J-shaped relationship between alcohol use and both major depression and anxiety disorder