Recurrent Mood Shifts of Premenstrual Dysphoric Disorder Can Be Mistaken for Rapid-Cycling Bipolar II Disorder

Sir: Some authors have postulated that the diagnosis of bipolar II disorder is underdiagnosed among outpatients attending mood disorder clinics. This diagnosis has been observed to occur more frequently in women in some, although not all, reports. Rapid-cycling variants of bipolar disorder occur approximately 3 to 5 times more frequently in women than in men.