Although approximately 75% of menstruating women have some physical, emotional, or behavioral symptoms premenstrually,1 only 3-8% of menstruating women have extremely distressing symptoms that interfere with their lifestyle, relationships, and occupational functioning.1-3 This severe form of premenstrual symptomatology is called premenstrual dysphoric disorder (PMDD).4 The Diagnostic and Statistical Manual of Mental Disorders (fourth edition) (DSM-IV) defines research diagnostic criteria, which emphasize the "on-offness" and the severity of the symptoms. "On-offness" means that the symptoms should be worst in the late luteal phase and absent in the midfollicular phase. The DSM-IV also excludes confounding disorders and requires confirmation of the diagnosis after 2 months of prospective daily ratings. These strict criteria reinforce the fact that not all women who have premenstrual symptoms have a mental illness. These criteria also allow PMDD to be differentiated from premenstrual syndrome (PMS), which is primarily reserved for milder physical and emotional symptoms.5 These criteria allow PMDD to be differentiated from premenstrual magnification (PMM), which occurs when symptoms of a concurrent psychiatric or medical disorder are magnified during the premenstruum.6
Department of Psychiatry, *†Department of Biomedical Sciences, †St. Joseph's Hospital, McMaster University, Hamilton, Ontario
Correspondence: Meir Steiner, MD, PhD, FRCP(C), Department of Psychiatry, St. Joseph's Hospital, 50 Charlton Avenue East, Hamilton, Ontario, Canada, L8N 4A6.