Treatment effects of alprazolam and imipramine: physiological versus subjective changes in patients with generalized anxiety disorder.

The correspondence between changes in physiological activity and somatic symptom reports was assessed in generalized anxiety disorder patients treated with alprazolam or imipramine. After 6 weeks, the two medications produced comparable reductions in self-reported somatic symptoms. However, patients taking alprazolam showed decreases in systolic blood pressure, epinephrine, and norepinephrine, and patients taking imipramine showed increases in heart rate, blood pressure, electromyographic activity, and norepinephrine. Thus, though the physiological changes associated with alprazolam treatment were consistent with changes in symptom reports, treatment with imipramine produced a desynchrony: patients reported significant decreases in cardiovascular symptoms and muscle tension in spite of the fact that heart rate, blood pressure, and electromyographic activity increased. Possible explanations for this counterintuitive phenomenon are discussed.