Mild Traumatic Brain Injury and Post-Traumatic Stress Disorder

Objective The primary objective of this study is to investigate the potential role of mild traumatic brain injury (mTBI) in the development of post-traumatic stress disorder (PTSD). We will characterize the central GABAergic system function in patients with PTSD after TBI (TBI-PTSD), subjects with TBI only (TBI-no PTSD), subjects with PTSD only (PTSD-no TBI ), and healthy non-TBI non-PTSD subjects (HC), using PET imaging with (11)C-Flumazenil (FMZ). Our hypothesis is that neuronal and axonal damage due to TBI results in GABAergic system dysfunction which could potentially lead to or contribute to the development of PTSD. We will also correlate the degree of (11)C-FMZ binding abnormalities with time elapsed since the original physical or psychological trauma in TBI-PTSD and PTSD-no TBI patients. Study Population Fifty-six male and female adult subjects will be recruited: 14 subjects with PTSD following an episode of non-penetrating mTBI (TBI-PTSD), 14 subjects with mTBI but no history of PTSD (TBI-no PTSD), 14 subjects with PTSD but no history of TBI (PTSD-no TBI), and 14 healthy volunteers (HC) with no PTSD and no history of TBI. The subjects will be recruited from the Walter Reed National Military Medical Center (WRNMMC). Design This is a prospective case-control study of the four subject groups mentioned above. Subjects will be stratified according to detailed psychiatric evaluation performed at WRNMMC. Subjects will not be treated with experimental therapies as part of the research study. This study will provide no direct benefit to subjects. Outcome Measures The main outcome measure will be (11)C-FMZ binding potential (BP) differences among these four subject groups. Other outcome measures will include Magnetic Resonance Imaging (MRI) anatomical findings and the correlation of (11)C-FMZ binding abnormalities with time elapsed since the original physical trauma in TBI-PTSD group or original psychological trauma in PTSD only group.