Pooled analysis of venlafaxine XR efficacy on somatic and psychic symptoms of anxiety in patients with generalized anxiety disorder.

Abstract

We evaluated the relative efficacy of venlafaxine XR on the psychic versus somatic symptoms of anxiety in patients with generalized anxiety disorder as determined by the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition. Data were pooled and analyzed from 1,841 patients with generalized anxiety disorder who participated in five short-term (8-week) double-blind, multicenter, placebo-controlled studies, two of which had long-term (6-month) extensions. Somatic and psychic anxieties were studied using the Hamilton rating scale for anxiety (HAM-A) factor scores. We examined response rates (> or =50% improvement over baseline severity score) in the overall population and in patients with mainly somatic symptomatology at baseline (somatizers). Venlafaxine XR significantly reduced factor scores for both psychic and somatic HAM-A factors compared with placebo, from the first and second weeks of treatment, respectively. Patients treated with venlafaxine XR had significantly higher rates of response than patients receiving placebo on the psychic (58% vs. 38%, P<.001 at week 8; 66% vs. 35% at week 24, P<.001) and somatic (56% vs. 43%, P<.001 at week 8; 67% vs. 47% at week 24, P<.001) factors of the HAM-A. There was a TreatmentxFactor interaction (P<.027) in response rates: Patients treated with venlafaxine showed similar somatic and psychic anxiety response rates, whereas placebo-treated patients showed higher somatic compared with psychic response rates. Somatizers showed similar rates of response to the total population for the somatic factor of the HAM-A in either treatment group. Patients with generalized anxiety disorder treated with venlafaxine XR showed similar absolute rates of response on somatic and psychic symptoms, but relative to patients treated with placebo, more improvement in psychic than somatic symptoms.