Quetiapine fumarate augmentation for patients with a primary anxiety disorder or a mood disorder: a pilot study

BACKGROUND Comorbid anxiety symptoms,in patients with a primary anxiety disorder or a mood disorder, leads to poor patient outcomes and burdens the healthcare system. This pilot study evaluated the feasibility of extended-release quetiapine fumarate (quetiapine XR) for the treatment of patients with either a primary anxiety disorder or a mood disorder with comorbid anxiety symptoms compared to a placebo, as an adjunct to antidepressant therapy. METHODS Thirty-nine patients with a diagnosis of a primary anxiety disorder or a mood disorder with comorbid anxiety symptoms were enrolled in this study. Patients with a stable dose of antidepressant therapy were randomized according to a 2:1 probability of receiving either quetiapine XR or a placebo adjunctive treatment for 8 weeks. The efficacy was assessed by the Hamilton Anxiety Rating Scale (HAM-A) and the Clinical Global Impression of severity (CGI-S) score at baseline, week 1, 4, and 8. RESULTS A total of 35 patients were included in this intention-to treat (ITT) population for the efficacy analysis (quetiapine XR: 22 patients; placebo: 13 patients). At week 4, statistically significant differences were observed on both the HAM-A score (p = 0.003) and the CGI-S score (p = 0.025), favouring the quetiapine XR (-13.00 ± 4.14) compared to placebo (-6.63 ± 5.42). However, no statistically significant difference was observed between the two groups with regard to changes from the baseline to week 8 on the HAM-A score (p = 0.332) or the CGI-S score (p = 0.833). CONCLUSIONS Augmentation of antidepressant treatment with quetiapine XR did not result in clinical improvement according to the outcome measure of anxiety using the HAM-A and CGI-S scores at week 8, among the patients with either a primary anxiety disorder or a mood disorder with comorbid anxiety symptoms. However, treatment with quetiapine XR as an adjunct to antidepressant therapy appeared to provide a short-term benefit at 4 weeks. Further study is needed with a larger sample size, randomized controlled design and control of the dosage prescribed. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT00912535.