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 ( < .001) and in the placebo group decreased from 24.21 ± 1.33 to 23.94 ± 1.66 ( = 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 ( < .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.