Smaller right hippocampus in war veterans with posttraumatic stress disorder

Chronic stress can putatively cause damage in the human hippocampus, but evidence of damage has not been consistently shown in studies on hippocampal morphology in posttraumatic stress disorder (PTSD). We compared hippocampal volumes in PTSD patients and normal subjects. Using a 3D T1-weighted GRE magnetic resonance imaging sequence, we measured hippocampal volumes in 15 war veterans with combat-related chronic PTSD and 15 case-matched normal controls. Although war veterans, our PTSD subjects were not professional soldiers and were mobilized shortly before they were exposed to a very specific combat-related trauma over a 3-day period. In our study, the period between traumatic exposure and imaging was considerably shorter, on average, 9 years, compared with at least two decades in previous studies on subjects with combat-related PTSD. Moreover, our subjects were free of any comorbidity, treatment or medication. The right hippocampus was significantly smaller in PTSD subjects than in healthy controls. The left hippocampus was also smaller in PTSD subjects than in controls, but the difference was not significant. In all PTSD subjects, the right hippocampus was smaller than the left (on average, 7.88%). Our results show smaller volume of the right hippocampus in PTSD patients than in normal subjects.