Effects of extended-release quetiapine fumarate on long-term functioning and sleep quality in patients with Generalized Anxiety Disorder (GAD): data from a randomized-withdrawal, placebo-controlled maintenance study.

Background: This analysis evaluated effects of quetiapine XR maintenance treatment on functioning and sleep in patients with GAD.

Methods: Analysis of patient-reported data from a randomized-withdrawal, double-blind, placebo-controlled study of quetiapine XR monotherapy in GAD. Following open-label run-in (4-8 weeks) and a 12-18-week stabilization phase (quetiapine XR 50, 150, or 300 mg/day), eligible patients were randomized to continue on quetiapine XR or receive placebo for up to 52 weeks. Primary variable was time to an anxiety event. Secondary variables included the Sheehan Disability Scale (SDS) and Pittsburgh Sleep Quality Index (PSQI).

Results: In total, 432 patients were randomized (quetiapine XR, N=216; placebo, N=216). The risk of an anxiety event was significantly reduced for quetiapine XR vs. placebo (HR 0.19; 95% CI 0.12, 0.31; p<0.001). Quetiapine XR was more effective than placebo at maintaining SDS total scores (LSM change: -0.19 vs. 1.01; p=0.017) and non-work-related SDS domain score 'family life/home responsibilities' (-0.13 vs. 0.32; p=0.011), but not 'social life' (0.05 vs. 0.34; p=0.114). Quetiapine XR was more effective than placebo at maintaining the work-related SDS domain score 'days lost' (-0.05 vs. 0.11; p=0.027), but not 'work/school' (-0.10 vs. 0.29; p=0.051) or 'days underproductive' (0.06 vs. 0.13; p=0.619). PSQI global scores were reduced from randomization with quetiapine XR vs. placebo (0.39 vs. 1.60; p<0.001).

Limitations: Lack of active-comparator arm, exclusion of patients with comorbid depression.

Conclusions: In patients with GAD, long-term treatment with quetiapine XR (50-300 mg/day) monotherapy was effective at maintaining improvements in functioning and sleep quality.