Objective: This study compared demographic and phenomenological variables between bipolar patients with and without rapid cycling as a function of bipolar I versus bipolar II status.
Method: The authors examined demographic, historical, and symptomatic features of patients with and without rapid cycling in a cross-sectional study of the first 500 patients with bipolar I or bipolar II disorder enrolled in the Systematic Treatment Enhancement Program for Bipolar Disorder, a multicenter project funded by the National Institute of Mental Health designed to evaluate the longitudinal outcome of patients with bipolar disorder.
Results: Rapid-cycling bipolar disorder occurred in 20% of the study group. Rapid-cycling patients were more likely to be women, although the effect was somewhat more pronounced among bipolar I patients than bipolar II patients. In addition, rapid-cycling bipolar patients experienced onset of their illness at a younger age, were more often depressed at study entry, and had poorer global functioning in the year before study entry than nonrapid-cycling patients. Rapid-cycling patients also experienced a significantly greater number of depressive and hypomanic/manic episodes in the prior year. A lifetime history of psychosis did not distinguish between rapid and nonrapid-cycling patients, although bipolar I patients were more likely to have experienced psychosis than bipolar II patients.
Conclusions: Patients with rapid-cycling bipolar disorder demonstrate a greater severity of illness than nonrapid-cycling patients on a number of clinical measures. This study highlights the need to refine treatments for rapid cycling to reduce the overall morbidity and mortality of patients with this illness course modifier.