Characterization of the longitudinal course of improvement in generalized anxiety disorder during long-term treatment with venlafaxine XR

Abstract

Objective: To characterize the response to the serotonin and norepinephrine reuptake inhibitor, venlafaxine extended release (XR), during the long-term treatment of generalized anxiety disorder.

Methods: Data from two double-blind, placebo-controlled, 6-month trials of venlafaxine XR for the treatment of generalised anxiety disorder were pooled. Criteria for response (> or = 50% improvement from baseline HAM-A score) and remission (HAM-A score < or = 7) and their temporal profile were used to characterize patient improvement over 6 months of treatment with venlafaxine XR and placebo.

Results: Venlafaxine XR was associated with significantly (P<0.001) higher response and remission rates (66 and 43%, respectively) compared with placebo (39 and 19%), regardless of the level of baseline anxiety. In the venlafaxine XR group, 61% of the patients who had responded but not remitted by week 8 showed remission by the end of 6 months. In comparison, only 39% of placebo responders who did not qualify for remission at the end of the first 8 weeks of therapy remitted by the end of the 6 months (P=0.007). Relapse occurred in 6% of venlafaxine XR-treated patients and 15% of placebo-treated patients (P<0.01).

Conclusion: This analysis provides further insight into the outcome of long-term treatment of generalised anxiety disorder with venlafaxine XR and shows for the first time that long-term treatment might be necessary to achieve and maintain remission of symptoms.