Remission of generalized anxiety disorder after 6 months of open-label treatment with venlafaxine XR.

BACKGROUND: Remission has become one of the leading outcome criteria in clinical trials. Data collected by this research group assessed the rate of remission after 6 months of treatment of generalized anxiety disorder (GAD) with venlafaxine XR, to search for predictors of remission and to define how early on in treatment later remission can be predicted. METHOD: Two hundred sixty-eight patients with a GAD diagnosis enrolled into an open-label 6-month-treatment trial with venlafaxine XR (75-225 mg/day). Remission was defined by a Hamilton anxiety scale total score ≤7. Logistic regression approaches were used to find out how early on in treatment later remission could be predicted, as well as to determine predictors of remission. In addition, adverse events were also followed over time. RESULTS: While the total enrolled patient sample (n = 268) had a remission rate of 53%, 6-month completers (n = 159) had a remission rate of 79%. The only statistically significant predictor of remission, independent of baseline anxiety and depression levels, was a low Eysenck neuroticism score. The remission status outcome could best be predicted after 8 weeks of treatment when a CGI-I score of 1 or 2 predicted later remission with 78% accuracy and later nonremission with 91% accuracy. The incidence of adverse events decreased over the 6-month period, with sexual adverse events decreasing the least. CONCLUSION: The only significant predictor of remission was a low score on the Eysenck neuroticism scale. The earliest reliable prediction of later remission, based on improvement, could be made after 8 weeks of treatment with 91% accuracy.