Introduction: Generalized anxiety disorder (GAD) is a chronic illness with psychic and somatic symptoms that do not respond uniformly in the first weeks of treatment.
Methods: A post-hoc analysis of pooled data from five placebo-controlled, double-blind, randomized studies in non-depressed GAD patients treated with venlafaxine extended release (ER) or placebo was performed to determine the temporal response of psychic and somatic symptoms to treatment over 8 weeks. Two of the studies included extension phases of up to 6 months, the results of which were also analyzed here.
Results: The earliest symptoms to respond included both psychic symptoms (anxious mood, tension, behavior at interview) and somatic muscular, cardiovascular, and respiratory symptoms. The last symptoms to respond included the psychic symptoms of insomnia and fear and the somatic sensory, gastrointestinal and autonomic symptoms, perhaps in part because of drug-related side effects. Continuing treatment beyond 8 weeks in venlafaxine ER responders for up to 6 months of total treatment results not only in additional improvement in early-responding symptoms, but also in the improvement of late-responding symptoms, perhaps due in part to the development of tolerance to antidepressant side effects.
Conclusion: Serious consideration should be given to maintaining partial responders to venlafaxine ER treatment on the same treatment for ≥3–6 months.