Sensitivity to 35% CO2 in healthy first-degree relatives of patients with panic disorder.

Abstract

The authors tested the hypothesis that hyperreactivity to CO2 in healthy subjects represents an underlying familial vulnerability to panic disorder. One vital-capacity inhalation of 35% CO2 and 65% O2 was administered to each of 84 patients with panic disorder, 23 healthy first-degree relatives of probands with panic disorder, and 44 healthy subjects with no family history of panic disorder. The first-degree relatives of the probands with panic disorder reacted significantly more than the healthy subjects and significantly less than the probands. These findings suggest an association between family history of panic disorder and hyperreactivity to 35% CO2 in healthy subjects.