Resting metabolic activity in the cingulate cortex and vulnerability to posttraumatic stress disorder.

CONTEXT Recent neuroimaging research has revealed functional abnormalities in the anterior cingulate cortex, amygdala, and hippocampus in individuals with posttraumatic stress disorder (PTSD). OBJECTIVE To determine whether resting functional abnormalities found in PTSD are acquired characteristics or familial risk factors. DESIGN Cross-sectional design including identical twins discordant for trauma exposure. SETTING Academic medical center. PARTICIPANTS Combat-exposed veterans with PTSD (n = 14) and their identical co-twins not exposed to combat (n = 14) as well as combat-exposed veterans without PTSD (n = 19) and their identical co-twins not exposed to combat (n = 19). MAIN OUTCOME MEASURES We used positron emission tomography and fluorodeoxyglucose 18 to examine resting regional cerebral metabolic rate for glucose (rCMRglu). RESULTS Veterans with PTSD and their co-twins had significantly higher resting rCMRglu in the dorsal anterior cingulate cortex/midcingulate cortex (dACC/MCC) compared with veterans without PTSD and their co-twins. Resting rCMRglu in the dACC/MCC in unexposed co-twins was positively correlated with combat exposure severity, PTSD symptom severity, and alcohol use in their exposed twins. CONCLUSIONS Enhanced resting metabolic activity in the dACC/MCC appears to represent a familial risk factor for developing PTSD after exposure to psychological trauma.