REDUCED BENZODIAZEPINE SENSITIVITY IN PATIENTS WITH PANIC DISORDER - COMPARISON WITH PATIENTS WITH OBSESSIVE-COMPULSIVE DISORDER AND NORMALSUBJECTS

Objective: The authors sought to replicate their previous finding of r educed response to diazepam in patients with panic disorder, to test w hether this effect was specific for panic disorder, and to determine w hether this reduced response ws merely an artifact of resistance to se dation from anxiety-related overarousal. Method: The effects of four i ncreasing intravenous doses of diazepam or saccadic eye movement veloc ity and accuracy (the latter being a saccadic variable that is unaffec ted by sedation), short-term memory, and self- and observer-rated seda tion were assessed in 18 patients with panic disorder, 15 patients wit h obsessive-compulsive disorder, and 14 normal comparison subjects. Th e ratios of effect to blood level areas under the curve for both ascen ding and descending limbs of the effect/blood level curves were compar ed for each variable. Results: Patients with panic disorder showed sig nificantly less diazepam effect on saccadic velocity and accuracy for the ascending limb of the blood level curve than comparison subjects. Patients with obsessive-compulsive disorder showed similar differences from comparison subjects but only for saccadic velocity. There were n o group differences in diazepam effects on memory and sedation. Conclu sions: Patients with panic disorder are less sensitive than comparison subjects to diazepam. Although this difference is not an artifact of resistance to sedation, it may not be specific for panic disorder but rather may reflect a more nonspecific aspect of anxiety disorders.