d,l-fenfluramine response in impulsive personality disorder assessed with [F-18]fluorodeoxyglucose positron emission tomography

Reduced serotonergic activity has been associated with impulsive aggression in personality disorder ecl patients in metabolite and pharmacologic chall enge studies. This study used positron emission tomography to explore wheth er reduced serotonergic function occurs in critical brain regions such as o rbital frontal and cingulate cortex that may play a role in modulating aggr ession. Six impulsive aggressive patients and five healthy volunteers were evaluated for changes in regional glucose metabolism after administration o f the serotonergic releasing agent d,l-fenfluramine (60 mg, p.o.) or placeb o. Volunteers demonstrated increases in orbital frontal and adjacent ventra l medial frontal cortex, cingulate, and inferior parietal cortex, whereas i mpulsive-aggressive patients showed no significant increases in glucose met abolism after fenfluramine in any region. Compared with volunteers, patient s showed significantly blunted metabolic responses in orbital frontal, adja cent ventral medial and cingulate cortex, but not in inferior parietal lobe . These results are consistent with reduced serotonergic modulation of orbi tal frontal, ventral medial frontal, and cingulate cortex in patients with impulsive-aggressive personality disorders. (C) 1999 American College of Ne uropsychopharmacology. Published by Elsevier Science Inc.