HEARTBEAT PERCEPTION AND PANIC DISORDER - POSSIBLE EXPLANATIONS FOR DISCREPANT FINDINGS

Results on cardiac awareness in panic disorder are inconsistent. The p resent study attempted to clarify whether differences in instructions or the inclusion of patients taking antidepressant medication could ac count for these inconsistencies. 112 patients with panic disorder with agoraphobia were compared to 40 normal controls on the heartbeat perc eption task developed by Schandry (1981) [Schandry, R., Psychophysiolo gy, 18,483-488] using a standard instruction (''count all heartbeats y ou feel in your body'') and a strict instruction (''count only those h eartbeats about which you are sure''). Superior heartbeat perception f or patients was only found with the standard instruction. Similarly, o nly with the standard instruction, patients taking medication affectin g the cardiovascular system performed worse than patients without medi cation, as expected based on the relationship between stroke volume an d heartbeat perception. The pattern of group differences indicates tha t agoraphobic patients have a better feeling for how fast their heart is beating than controls although these differences may be due to a te ndency to interpret weak sensations as heartbeats. Furthermore, we tes ted in a subgroup of 40 patients whether cardiac awareness changes wit h exposure treatment. No changes in heartbeat perception were observed .