A recent study from the Harvard School of Public Health found that drinking 2-4 cups of coffee per day may cut suicide risk for women and men in half. Apparently, coffee somehow causes the brain to produce larger quantities of the neurotransmitters dopamine, noradrenaline, and serotonin—the same chemicals that are affected by many popular antidepressants, including Prozac and Paxil.
The researchers, led by Michel Lucas, tracked caffeine-consumption data from about 200,000 people. They looked at all sources of caffeine, including chocolate, coffee, energy drinks, soda, and tea. And while all of them are helpful in improving mood, coffee was by far the most common—and the most effective.
Another study, done a few years before, also found that coffee has an antidepressant quality–but it kicked in only after four cups per day.
Hang on. Before you go out and buy yourself an expensive espresso maker, Lucas says that “…there is little further benefit for consumption above 2-3 cups/day or 400 mg of caffeine/day.” Plus, a large-scale study done in Finland found that drinking eight or nine cups of coffee per day actually increased the risk of suicide.
The study was published in the The World Journal of Biological Psychiatry. You can read an excerpt here.