Is quetiapine effective for obsessive and compulsive symptoms in patients with bipolar disorder? A randomized, double-blind, placebo-controlled clinical trial

Background The aim of this study is to examine the effects of quetiapine as an adjuvant treatment for obsessive-compulsive (OC) symptoms in patients with bipolar disorder (BD) type I. Methods In this 8-week double-blind placebo-controlled randomized clinical trial, 47 patients with BD in euthymic phase that had OC symptoms were randomly allocated to receive either quetiapine or placebo plus their routine medications (lithium + clonazepam). Yale-Brown Obsessive-Compulsive Scale (YBOCS) was used to assess the outcomes. Adverse effects were also recorded. Results Of 47 BD patients with OC symptoms that were randomly allocated in two groups of quetiapine (n = 24) and placebo group (n = 23), 40 patients (20 in quetiapine group and 20 in placebo group) completed the trial. Throughout the trial, the mean score of YBOCS in the quetiapine group dropped from 24.37 +/- 1.51 to 15.26 +/- 1.16 (P < .001) and in the placebo group decreased from 24.21 +/- 1.33 to 23.94 +/- 1.66 (P = 1.97). At the end of the study, 12 (60%) patients in the quetiapine group and 1 (5%) patient in the placebo group had more than 34% decline in YBOCS score (P < .001). No serious adverse effects were reported in two groups. Conclusions Our double-blind placebo-controlled clinical trial showed that quetiapine may be an effective adjuvant agent for reducing OC symptoms in BD patients.