Cigarette smoking, alcohol intoxication and major depressive episode in a representative population sample

Objective-This study investigated the associations of cigarette smoking and alcohol intoxication with major depressive episode. Design-Major depressive episode during the past 12 months was assessed in a national representative cross sectional study using the Short Form of the University of Michigan version of the Composite International Diagnostic Interview (the UM-CIDI Short Form). Subjects-A random sample of 5993 non-institutionalised Finnish people aged 15-75 years was interviewed as a part of the 1996 Finnish Health Care Survey. Results-In logistic regression models the factors associated with major depressive episode in the past 12 months were smoking 10 or more cigarettes daily (odds ratio (OR) 2.26; 95% confidence intervals (95% CI) 1.68, 3.04) and alcohol intoxication at least once a week (OR 2.99; 95%CI 1.70, 5.25). Their effects were independent of each other, and remained significant even after adjusting for other major risk factors (marital status, education, unemployment and chronic diseases). The attributable proportion (a measure of the impact of the risk factors of the disease on the population) for daily smoking of 10 or more cigarettes was 0.15, and for alcohol intoxication at least once a week 0.04. Conclusion-Cigarette smoking and alcohol intoxication seem to be important risk factors for major depressive episode. In this population the impact of smoking was greater.