Focal Brain Damage Protects Against Post-Traumatic Stress Disorder in Combat Veterans

Post-traumatic stress disorder (PTSD) has consistently been linked in neuroimaging studies to reduced activity in the ventromedial prefrontal cortex (vmPFC) and heightened amygdala responses, but correlational imaging alone cannot establish whether these patterns cause the disorder or simply accompany it. This study approached the question causally by evaluating Vietnam War veterans who had sustained penetrating head injuries in addition to emotionally traumatic combat events, comparing the occurrence of PTSD across groups defined by lesion location. Veterans with substantial damage to the vmPFC, or to an anterior temporal region including the amygdala, developed PTSD far less often than veterans with lesions elsewhere in the brain or with no brain injury at all — indeed, not a single veteran with amygdala damage ever received a lifetime diagnosis. The findings identify the vmPFC and the amygdala as causally involved in the pathogenesis of PTSD and suggest that treatments aimed at selectively inhibiting these regions could offer a therapeutic route for the disorder.