Women complain about it. Men joke about it. And complain about it. Now, research conducted at the University of Toronto suggests that PMS doesn’t even exist. It’s true. A University of Toronto news release reports that an analysis of 41 research studies that tracked women’s daily moods through their menstrual cycles found “no clear link between women’s negative moods and the pre-menstrual phase of their cycles.” In fact, only six of the papers showed any association between negative moods and the pre-menstrual phase. Gillian Einstein, director of U of T’s collaborative program in Women’s Health and one of several experts involved in the study, points out that entire industries have been built around the idea that women are moody, irrational — even unstable — in the phase leading up to menstruation. “Our review,” says Einstein, “will be surprising to many people.” Yes. It will. Read more from the University of Toronto. Read the study in Gender Medicine.