To the Editor.—
Roy-Byrne and colleagues demonstrated that, in response to intravenous administration of diazepam, saccadic eye movement velocity decreased less in patients with panic disorder than in nonanxious control subjects. While the authors' conclusions were cautious, their discussion favored a disorder rather than an arousal-related diazepam effect. The authors based their arguments on the lack of correlations between anxiety measures and eye movement velocity and on the lack of such an effect in a small sample of patients with generalized anxiety disorder (GAD).Evidence, however, favors the interpretation that the effects were primarily arousal related. The authors compared nonanxious controls with panic disorder patients. A number of studies have suggested that panic disorder patients tend to respond more strongly to stress, both subjectively and physiologically than nonanxious control patients or GAD patients.2 Thus, it is possible that the panic disorder patients were more aroused than the controls. The