Brain Volume in Veterans: Relationship to Posttraumatic Stress Disorder and Mild Traumatic Brain Injury

Objective: Clarify associations between diagnosis of posttraumatic stress disorder (PTSD) and deployment traumatic brain injury (TBI) on salient regional brain volumes in returning combat veterans. Participants: Iraq and Afghanistan era combat veterans,N= 163, 86.5% male. Main Measures: Clinician-administered PTSD Scale (CAPS-5), Mid-Atlantic MIRECC Assessment of TBI (MMA-TBI), magnetic resonance imaging. Methods: Hierarchical regression analyses evaluated associations and interactions between current and lifetime PTSD diagnosis, deployment TBI, and bilateral volume of hippocampus, anterior cingulate cortex, amygdala, orbitofrontal cortex, precuneus, and insula. Results: Deployment TBI was associated with lower bilateral hippocampal volume (P= .007-.032) and right medial orbitofrontal cortex volume (P= .006). Neither current nor lifetime PTSD diagnosis was associated with volumetric outcomes beyond covariates and deployment TBI. Conclusion: History of deployment TBI is independently associated with lower volumes in hippocampus and medial orbitofrontal cortex. These results support TBI as a potential contributing factor to consider in reduced cortical volume in PTSD.