Diagnosis and treatment of rapidly cycling bipolar disorder

The conceptualization of rapidly cycling bipolar disorder remains controversial. The DSM-IV definition of rapid cycling, although very reliable, may be not sufficiently inclusive (i.e., it may exclude patients with very short episodes of very high frequency, who are very typical in terms of external validators, and are currently regarded as rapid cyclers by many researchers and clinicians). Moreover, the addition of the requirement of pole switching (i.e., at least one direct transition from one polarity of mood to the other) during the previous year may increase the prognostic and treatment response implications of the diagnosis of rapid cycling. It is commonly held that rapid cyclers are refractory to lithium prophylaxis. However, currently available research evidence suggests that lithium prophylaxis does exert an impact on the course of rapidly cycling bipolar disorder. One double-blind crossover study supports the clinical impression that the combination of at least two mood stabilizers may be needed in most rapid cyclers.