CEREBRAL VASODILATION AND VASOCONSTRICTION ASSOCIATED WITH ACUTE ANXIETY

A randomized, between-groups repented measures design was used to eval uate changes in cerebral bloodflow (CBF), rating scales, and physiolog ic indices under resting conditions, duping 5% CO2 inhalation in combi nation with epinephrine or saline infusions, in generalized anxiety di sorder patients and controls. Subjects were divided into those with de creased anxiety and mild and more severe anxiety increase. The first g roup was found to have most pronounced CBF increase during CO2 inhalat ion, with the second group showing less marked increase, and the last group the least increase. In animals, sympathetic activation limits hy percapnic cerebral vasodilation. Thus, the restricted hypercapnic cere bral vasodilation during severe anxiety may be mediated through cervic al sympathetic fibers, which innervate cerebral vessels. (C) 1997 Soci ety of Biological Psychiatry.