There are good population-based data showing that the onset of depression increases in women around periods of hormonal change. This would be during puberty, pregnancy, postpartum (after giving birth), and perimenopause (the period around menopause). The possible reasons for this are being studied by neuroscientists. Understanding the mechanisms behind the increase in the incidence of depression may lead to new treatments. For example, a group at the National Institute of Mental Health led by David Rubinow, M.D., is studying the effects of withdrawing estradiol (the main circulating estrogen) on mood in perimenopausal women. This is a large and interesting topic worthy of study in and of itself.