Efficacy and tolerability of quetiapine in the treatment of bipolar disorder: preliminary evidence from a 12-month open-label study

Background: The literature on the use of quetiapine for the treatment of bipolar disorder (BD) is limited to case reports, and there are no systematic studies on the efficacy of quetiapine in the prophylactic treatment of BD. The aim of the present study was to compare the efficacy of flexible doses of quetiapine and well established mood stabilizers in the maintenance treatment of BD. Methods: Twenty-eight DSM-IV BD outpatients were consecutively recruited into the study and were randomized to receive one of two open-label treatments, with quetiapine or classical mood stabilizers at flexible doses for 12 months. Clinical assessment was carried out using BPRS, CGI, YMRS and the 21-item HAM-D at baseline (T0) and every 2 months until the end of the study. ANOVAs with repeated measures were applied to the rating scale scores considering the time and the treatment group as main factors. Results: All patients experienced a significant improvement on the BPRS, CGI and HAM-D scores, with no significant side-effects and a good compliance. Limitations: This study should be considered preliminary given the small sample size investigated and the open-label design. Conclusions: If these results will be replicated on larger samples and in controlled studies, there could be relevant implications for the use of quetiapine as an alternative maintenance treatment for BD.