Some studies shows correlation of reduced hippocampus volume and posttraumatic stress disorder ( PTSD ) . A study of Vietnam War combat veterans with PTSD showed a 20 % reduction in the volume of their hippocampus compared with veterans having suffered no such symptoms . This finding was not replicated in chronic PTSD patients traumatized at an air show plane crash in 1988 ( Ramstein , Germany ) . A 2016 study strengthened theory that a smaller hippocampus increases the risk for post-traumatic stress disorder , and a larger hippocampus increases the likelihood of efficacious treatment
air show plane crash in 1988
Ramstein air show disaster
Hippocampus