ABSTRACT
OBJECTIVE: Neuroimaging studies have revealed functional abnormalities in the anterior cingulate cortex in posttraumatic stress disorder (PTSD). The goal of this study was to determine whether hyperresponsivity of the dorsal anterior cingulate in PTSD is an acquired characteristic or a familial risk factor. METHOD: Using a case-control twin design, the authors studied combat-exposed veterans with PTSD (N=12) and their identical combat-unexposed co-twins (N=12), as well as combat-exposed veterans without PTSD (N=14) and their identical combat-unexposed co-twins (N=14). Participants underwent functional MRI during completion of the Multi-Source Interference Task, which reliably activates the dorsal anterior cingulate. RESULTS: Combat-exposed veterans with PTSD and their unexposed co-twins had significantly greater activation in the dorsal anterior cingulate and tended to have larger response time difference scores, as compared to combat-exposed veterans without PTSD and their co-twins. Dorsal anterior cingulate activation in the exposed twins was positively correlated with their PTSD symptom severity. Dorsal anterior cingulate activation in the unexposed twins was positively correlated with their combat-exposed co-twins' PTSD symptom severity, but not with depression or alcohol use severity in the combat-exposed co-twins. CONCLUSIONS: Hyperresponsivity in the dorsal anterior cingulate appears to be a familial risk factor for the development of PTSD following psychological trauma.
Subject(s)
Attention/physiology , Combat Disorders/genetics , Combat Disorders/physiopathology , Diseases in Twins/genetics , Diseases in Twins/physiopathology , Gyrus Cinguli/physiopathology , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Pattern Recognition, Visual/physiology , Problem Solving/physiology , Stress Disorders, Post-Traumatic/genetics , Stress Disorders, Post-Traumatic/physiopathology , Vietnam Conflict , Arousal/genetics , Arousal/physiology , Brain Mapping , Discrimination, Psychological/physiology , Female , Humans , Male , Middle Aged , Oxygen Consumption/physiology , Psychomotor Performance/physiology , Reaction Time/physiology , Stress Disorders, Post-Traumatic/diagnosis , Stress Disorders, Post-Traumatic/psychology , Twins, MonozygoticABSTRACT
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.
