Characteristics of rapid cycling bipolar-I patients in a bipolar speciality clinic

Objective: To investigate the characteristics of patients with rapid cycling bipolar illness. Method: The charts of bipolar patients treated at the Massachusetts General Hospital Bipolar Clinic were reviewed for age of the first affective episode, demographics and history of rapid cycling. Results: Data from 223 bipolar-I–II patients, of whom 11.7% were bipolar-II, were obtained, and only the data from 197 bipolar-I patients were analyzed. Forty-three percent of them had a positive history of rapid cycling. Rapid cycling was more common in women, with rapid cycling females having an earlier age of onset than non-rapid cycling bipolar-I females. No such association was found in bipolar-I males. In addition, with respect to current age, rapid cyclers were younger than non-rapid cyclers in bipolar-I females. No association was found for duration of illness. Conclusions: Women with bipolar-I illness have an increased probability of rapid cycling, which may still be increased in those with an early onset. Therefore, biological factors, such as sex and age onset, appear to be relevant to the physiology of rapid cycling. The retrospective design and the selected population of bipolar-I patients from an academic tertiary-referral center may limit the generalizability of our results.