Researchers at the Harvard School of Public Health have released a study showing that women who drink coffee regularly have a lower incidence of depression.

50,000 women participated in the study that took place over 10 years. The results show that women who consume two to three cups of coffee a day are 15 percent less likely to be depressed. Women who consume four cups of coffee or more per day are 20 percent less likely to suffer from depression.

Today is a particularly good day for this news, as it's International Coffee Day. Several coffee chains are offering free coffee drinks today to celebrate this holiday, including Caribou Coffee, where coffee drink are buy-one-get-one today.