Harvard study links coffee with reduced suicide risk

In the latest major study on coffee, a group of Harvard researchers are adding evidence to past research that suggests caffeinated coffee is a mild anti-depressant.

The researchers, who published their study in The World Journal of Biological Psychiatry, discovered a link between drinking 2-4 cups of caffeinated coffee each day and a lower risk of suicide among adult men and women.

They analyzed data from three large-scale U.S. studies that followed a total of over 200,000 people for at least 16 years from 1988 to 2008. Across all three studies, coffee accounted for the majority of caffeine consumed at 71 per cent of the total.

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An analysis revealed that people who drank 2-4 cups of caffeinated coffee a day (the equivalent of about 400 mg of caffeine) had a 50 per cent lower risk of suicide than those who didn't drink coffee, drank decaf, or drank fewer than two cups each day.

The researchers believe that the caffeine in coffee acts as a mild anti-depressant and increases feel-good chemicals (neurotransmitters) like serotonin, dopamine and noradrenalin.

“We identify caffeine as the most likely candidate of any putative protective effect of coffee,” says lead researcher Michel Lucas, research fellow in the Department of Nutrition.

In spite of the findings, the authors do not recommend that depressed adults increase caffeine consumption because an increase could result in unpleasant side effects.

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“Overall, our results suggest that there is little further benefit for consumption above two to three cups/day or 400 mg of caffeine/day,” the authors write.

The unpleasant side effects relates to the fact that caffeine stimulates the central nervous system. Due to this significant effect is has on the body, the new edition of DSM-5 lists caffeine intoxication and withdrawal as psychiatric disorders.

Previous research has linked caffenine with a lower risk of stroke, breast and skin cancer, heart failure, Alzheimer's and diabetes.