“Comparing the hippocampal volume of mentally healthy subjects and patients with PTSD, DDNOS, and DID, thus patients with increasing levels of dissociation, an increasingly smaller volume is observed: PTSD (primary structural dissociation), approximately -10%; DDNOS (secondary structural dissociation), approximately -15%; and DID (tertiary structural dissociation), approximately -20%. These findings are characterized by a remarkable relationship: the more severe the structural dissociation of the personality, the smaller the hippocampal volume. Furthermore, Ehling et al. (2008) found high correlations between the volume of these brain structures and psychoform and somatoform symptoms, as well as with the severity of the reported potentially traumatizing events. Correlations between the volume of these brain structures and the degree of general psychopathology and fantasy-proneness were lower or statistically nonsignificant.” BrainPtsdDissociative Identity DisorderDissociative DisorderDdnosOsdd Author:Onno van der Hart