Efficacy of Quetiapine Monotherapy in Rapid-Cycling Bipolar Disorder in Comparison With Sodium Valproate

Abstract

Rapid-cycling bipolar disorder is often characterized by a lack of response to psychopharmacological treatment, and a standard therapy has not been developed yet. The aim of this study was to examine the long-term efficacy and safety of a monotherapy with quetiapine or sodium valproate (VPA) in patients with rapid-cycling bipolar disorder. This open-label, randomized, parallel group monotherapy pilot study was conducted at 3 German centers. A sample of 38 remitted or partly remitted patients with bipolar disorder and rapid cycling (quetiapine n = 22; VPA n = 16) were treated with quetiapine or VPA (flexible dose design) for 12 months. Forty-one percent of the patients with quetiapine and 50% with VPA completed the trial. On the basis of ITT-LOCF, Life Chart Method data showed that patients being treated with quetiapine had significantly less moderate to severe depressive days than patients on VPA (mean +/- SD, 11.7 +/- 16.9 days vs 27.7 +/- 24.9 days; P = 0.04) while they did not differ in the number of days with manic or hypomanic symptoms. Furthermore, according to the Clinical Global Impression Scale, bipolar version, the responder rates tended to be higher for quetiapine than for VPA. There were no differences found evaluating the Hamilton Depression Rating Scale, the Montgomery-Asberg Depression Scale, and the Young Mania Rating Scale. The incidence of adverse events, especially of orthostatic dysregulation, sedation, and weight gain, was significantly higher in the quetiapine group. In this study, quetiapine was more effective than VPA on the number of depressive days and similar to VPA in the treatment of manic symptoms. Quetiapine was associated with a greater incidence of side effects, particularly orthostatic dysregulation, sedation, and weight gain.