Source
Department of Clinical and Biomedical Sciences: Barwon Health, The University of Melbourne, PO Box 281, Geelong 3220, Australia. juliep@barwonhealth.org.au
Abstract
BACKGROUND:
Smoking is disproportionately prevalent among people with psychiatric illness.
AIMS:
To investigate smoking as a risk factor for major depressive disorder.
METHOD:
A population-based sample of women was studied using case-control and retrospective cohort study designs. Exposure to smoking was self-reported, and major depressive disorder diagnosed using the Structured Clinical Interview for DSM-IV-TR (SCID-I/NP).
RESULTS:
Among 165 people with major depressive disorder and 806 controls, smoking was associated with increased odds for major depressive disorder (age-adjusted odds ratio (OR)=1.46, 95% CI 1.03-2.07). Compared with non-smokers, odds for major depressive disorder more than doubled for heavy smokers (>20 cigarettes/day). Among 671 women with no history of major depressive disorder at baseline, 13 of 87 smokers and 38 of 584 non-smokers developed de novo major depressive disorder during a decade of follow-up. Smoking increased major depressive disorder risk by 93% (hazard ratio (HR)=1.93, 95% CI 1.02-3.69); this was not explained by physical activity or alcohol consumption.
CONCLUSIONS:
Evidence from cross-sectional and longitudinal data suggests that smoking increases the risk of major depressive disorder in women.