PhD ceremony Ms. S. Chalavi: The traumatized brain. Gray and white matter morphology in dissociative identity disorder and posttraumatic stress disorder

PhD ceremony: Ms. S. Chalavi, 12.45 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: The traumatized brain. Gray and white matter morphology in dissociative identity disorder and posttraumatic stress disorder

Promotor(s): prof. A. Aleman, prof. D.J. Veltman

Faculty: Medical Sciences

Despite the mentioning of dissociative identity disorder (DID) in the DSM-3 through DSM-5, there is ongoing debate about its diagnosis, aetiology, and theoretical basis. This may be related to the lack of empirical research of the neurobiological correlates of DIS. This thesis aims to provide such neuroscientific knowledge using structural imaging techniques.

We found that both patients with dissociative identity disorder and patients with posttraumatic stress disorder had smaller gray matter of the frontal, temporal and insular cortices and whole cortex and abnormality of the white matter of the brain. In addition, hippocampus was smaller in patients with dissociative identity disorder compared to healthy volunteers and the severity of hippocampal reduction correlated with the severity of childhood traumatisation. Furthermore, we found that dissociative identity disorder was associated with structural abnormality of the inferior parietal cortex and dorsal striatum compared to patients with posttraumatic stress disorder and healthy volunteers and these abnormalities were linked to the dissociative symptoms. Findings presented in this thesis mainly provide objective empirical support in favour of a trauma-related aetiology for DID and thereby may help in better understanding the neural mechanism underlying dissociative identity disorder.