In the past year, randomized controlled clinical trials of treatments for clearly diagnosed premenstrual syndrome reported efficacy for serotonergic antidepressants and a gonadotropin-releasing hormone agonist. Preliminary data suggested efficacy for spironolactone and a carbohydrate-rich beverage. Several neuroendocrine studies have contributed to a growing list of findings that suggest an underlying neurobiological vulnerability in premenstrual syndrome.