Randomized, placebo-controlled trial of quetiapine XR and divalproex ER monotherapies in the treatment of the anxious bipolar patient

BackgroundAnxiety disorders complicate the treatment of bipolar disorder but are seldom the focus of bipolar treatment studies.MethodsThe anxiolytic effect of quetiapine XR 50-300 mg/day compared to divalproex ER (500-3000 mg/day) was tested in an 8-week, double-blind, placebo-controlled, randomized clinical trial in 149 patients with bipolar disorder and a co-occurring panic disorder or GAD. The primary efficacy measure was the Clinician Global Improvement-21 Anxiety Scale (CGI-21). Secondary measures included the Hamilton Anxiety Scale (HAM-A) and Sheehan Panic Disorder Scale (SPS).ResultsRepeated measures last-observation-carried-forward (LOCF) analyses of variance demonstrated significant treatment-by-time interaction effects on 3 of the 4 anxiety measures. Quetiapine XR at a mean endpoint dose of 186 mg/day produced rapid sustained improvements relative to baseline, divalproex ER and placebo on anxiety. Mean baseline-to-endpoint improvement was significantly greater for quetiapine XR compared to divalproex ER and placebo on the HAM-A and SPS. Both active medications were well tolerated, but weight gain was higher on quetiapine XR.LimitationsThe study was limited to 8 weeks and to patients with bipolar disorder and comorbid panic disorder or GAD. The results may not be applicable to quetiapine XR as an add-on treatment to mood stabilizers or to bipolar disorder comorbid with other anxiety disorders.ConclusionsQuetiapine XR in a dose range of 50-300 mg/day appears to reduce anxiety in bipolar patients with comorbid panic disorder or GAD treated for 8 weeks. The efficacy of other second-generation antipsychotics and mood stabilizers in patients with bipolar disorder and a co-occurring anxiety disorder should be investigated in double-blind, placebo-controlled studies.