'Rapid cycling' bij bipolaire stoornissen: Subtype of prototype?

BACKGROUND: Rapid cycling is a form of bipolar disorder that is characterised by frequent episodes and poor response to pharmacotherapy. It is uncertain whether rapid cycling is a distinct subtype of bipolar disorder, possibly with a different pathophysiological background. AIM: To determine whether rapid cycling and can be distinguished from non-rapid cycling bipolar disorder on the grounds of patient characteristics, clinical characteristics other than episode frequency, and treatment response. METHOD: We reviewed and meta-analysed the existing literature. In addition, we conducted a prospective study of 539 bipolar patients, adopting both a dichotomous and a dimensional approach to episode frequency. RESULTS: Rapid cycling was associated with various demographic, biographic, and psychiatric factors. These gradually became more prevalent with increasing episode frequency, but there was no evidence of a sharp division between rapid and non-rapid cycling. Depressive symptoms predominated in bipolar patients; manic symptoms increased as a function of episode frequency. Lithium remains the treatment of choice in the case of rapid cycling: there is no evidence that other mood stabilisers are more effective. CONCLUSION: Rapid cycling is not a distinct subtype of bipolar disorder, but should be regarded as one of the two extremities on a continuum of episode frequencies.