Premenstrual dysphoric disorder (PMDD) appears in the appendix of the DSM-IV under the heading 'depressive disorder not otherwise specified'. Yet, recently, a group of experts reached a consensus that PMDD is a distinct clinical entity with characteristic symptoms of irritability, anger, internal tension, dysphoria, and mood lability. PMDD is the more severe form of premenstrual symptomatology, whereas premenstrual syndrome (PMS) is milder and more prevalent and both must be differentiated from premenstrual magnification/exacerbation of an underlying major psychiatric disorder or a medical condition. Accurate assessment and diagnosis of significant premenstrual symptomatology is paramount and can be influenced by subjective perception, retrospective versus prospective reporting, and cultural context. The serotonergic system, which is in a close reciprocal relationship with the gonadal hormones, has been identified as the most plausible target for intervention. Results from randomized placebo-controlled trials in women with PMDD have clearly demonstrated that serotonin reuptake inhibitors (SSRIs), with daily or intermittent dosing, have excellent efficacy and minimal adverse effects and should be considered first-line treatment. Luteal phase only SSRI administration may offer an attractive treatment option for a disorder that is itself intermittent. Hormonal interventions, in particular the suppression of ovulation will eliminate premenstrual symptomatology; however, the benefits-risk ratio of these approaches should be carefully evaluated with the patient.