Quetiapine monotherapy in acute treatment of generalized anxiety disorder: a systematic review and meta-analysis of randomized controlled trials

Background: Some studies have indicated the efficacy of quetiapine in the treatment of generalized anxiety disorder (GAD). Objective: The purpose of this study was to systematically review the efficacy, acceptability, and tolerability of quetiapine in adult patients with GAD. Methods: The SCOPUS, MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases were searched in April 2015. All randomized controlled trials (RCTs) of GAD were considered to be included in this meta-analysis. All RCTs of quetiapine in GAD patients providing endpoint outcomes relevant to severity of anxiety, response rate, remission rate, overall discontinuation rate, or discontinuation rate due to adverse events were included. The version reports from suitable clinical studies were explored, and the important data were extracted. Measurement for efficacy outcomes consisted of the mean-changed scores of the rating scales for anxiety, and response rate. Results: A total of 2,248 randomized participants in three RCTs were included. The pooled mean-changed score of the quetiapine-treated group was greater than that of the placebo-treated group and comparable to selective serotonin reuptake inhibitors (SSRIs). Unfortunately, the response and the remission rates in only 50 and 150 mg/day of quetiapine-XR (extended-release) were better than those of the placebo. Their response and remission rates were comparable to SSRIs. The rates of pooled overall discontinuation and discontinuation due to adverse events of quetiapine-XR were greater than placebo. Only the overall discontinuation rate of quetiapine-XR at 50 and 150 mg/day and the discontinuation rate due to adverse events of quetiapine-XR at 50 mg/day were comparable to SSRIs. Conclusion: Based on this meta-analysis, quetiapine-XR is efficacious in the treatment of GAD in adult patients. Despite its low acceptability and tolerability, the use of 50-150 mg/day quetiapine-XR for adult GAD patients may be considered as an alternative treatment. Further well-defined studies should be conducted to warrant these outcomes.