Depression Is Less Common in Women Who Drink Coffee
Four or more cups daily seemed to protect against developing depression.
One prospective study involving men showed a reduced risk for depression with increased coffee consumption (Public Health Nutr 2010; 13:1215), and several studies have shown an association between increased coffee consumption and decreased risk for suicide. Using data from the Nurses’ Health Study, investigators studied about 50,000 women who were free of depression at baseline; coffee consumption and new diagnoses of depression were documented during 10 years of follow-up.
In analyses adjusted for numerous clinical and demographic variables, risk for depression in women who drank four or more cups of coffee daily was 20% lower than in women who drank one cup or less weekly. No association was observed between risk for depression and consumption of either decaffeinated coffee or caffeine from other sources (e.g., tea, chocolate); however, noncoffee sources probably contributed too little caffeine for meaningful assessment.
Comment: These results are biologically plausible, because caffeine affects dopaminergic transmission as an adenosine-receptor antagonist. The finding that decaffeinated coffee doesn’t lower risk for depression suggests that caffeine is the active component. However, confirmatory data from randomized trials would be preferable before we use these findings to make clinical recommendations.
Thomas L. Schwenk, MD
Published in Journal Watch General Medicine October 6, 2011