GFAP and post-traumatic stress disorder: Different theories have been proposed to explain this discordant relation between injury severity and symptomology.39 After identifying a negative association between PTSD and GFAP levels following mTBI in the TRACK-TBI cohort, it was hypothesized that this relationship may partially result from a prolonged duration of post-traumatic amnesia (PTA) in individuals with more severe glial injury.13 This may lead to both a higher GFAP and interference with encoding and/or consolidating memory, protecting against PTSD.