Caffeine reduces risk of depression in women

Women who drink more than 1 cup of caffeinated coffee a day may significantly lower their risk of depression, and the more coffee they drink the greater the risk reduction, new research published in the Archives of Internal Medicine(2011;171[17]:1571-1578) suggests.

The 10-year longitudinal study by researchers from the Harvard University School of Public Health examined 50,739 women enrolled in the Nurses’ Health Study, none of whom had been diagnosed with depression when the study began. Their mean age was 63 years. When the researchers recorded the number of women who developed clinical depression and compared it with caffeine consumption (80% in coffee, 12% in tea, and 5% in caffeinated soft drinks), they found that women who drank 2 to 3 cups of coffee daily had a 15% lower risk of depression than those who consumed 1 cup or less per week. Those who drank 4 cups or more per day had a 20% lower risk of depression. Women who drank 1 cup of coffee per day also reduced their depression risk, but not as much as those who consumed more.

“Our results support a possible protective effect of caffeine, mainly from coffee consumption, on risk of depression,” the researchers write. “These findings are consistent with earlier observations that suicide risk is lower among persons with higher consumption of coffee.”

Speculating on caffeine’s effect on depression, the researchers observe that it affects brain function by acting as an antagonist to adenosine A2A, thus helping modulate dopaminergic transmission. They note that caffeine might also influence non-dopaminergic mechanisms such as the release of acetylcholine and serotonin. 

Further research is needed, they emphasize, to confirm their findings and “determine whether usual caffeinated coffee consumption may contribute to prevention or treatment of depression.”

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