Risk factors for rapid cycling in bipolar disorder

Objectives: The aim of this study was to investigate the clinical factors associated with the development of rapid cycling, as well as to elucidate the role of antidepressants. Methods: The present study (NCT01503489) is a prospective, naturalistic cohort study conducted in a sample of 289 patients diagnosed with bipolar disorder followed and treated for up to 14 years. The patients were divided into two groups on the basis of the development of a rapid cycling course (n = 48) or no development of such a course (n = 241), and compared regarding sociodemographic, clinical, and outcome variables. Results: Among the 289 patients, 48 (16.6%) developed a rapid cycling course during the follow-up. Several differences were found between the two groups, but after performing Cox regression analysis, only atypical depressive symptoms (p = 0.001), age at onset (p = 0.015), and number of suicide attempts (p = 0.030) persisted as significantly associated with the development of a rapid cycling course. Conclusions: The development of rapid cycling during the course of bipolar disorder is associated with a tendency to chronicity, with a poorer outcome, and with atypical depressive symptomatology. Our study also suggests that the development of rapid cycling is associated with a higher use of antidepressants.