Generate text that best answers this question: serotonin
Heavy coffee drinking and the risk of suicide.
Earlier research has implicated coffee drinking as a possible protective factor for suicide. We followed-up 43,166 subjects for the mean 14.6 years, and 213 suicides were committed. Daily coffee drinking had a J-shaped association with the risk of suicide. Using the Cox model we controlled for potential covariates, and found that among heavy coffee drinkers (> or = 8 cups/day) the risk of suicide was 58% higher compared with more moderate drinkers.