ABSTRACT
OBJECTIVE: To examine the two constitutes of cortical volume (CV), that is, cortical thickness (CT) and surface area (SA), in individuals with dissociative identity disorder (DID) with the view of gaining important novel insights into the underlying neurobiological mechanisms mediating DID. METHODS: This study included 32 female patients with DID and 43 matched healthy controls. Between-group differences in CV, thickness, and SA, the degree of spatial overlap between differences in CT and SA, and their relative contribution to differences in regional CV were assessed using a novel spatially unbiased vertex-wise approach. Whole-brain correlation analyses were performed between measures of cortical anatomy and dissociative symptoms and traumatization. RESULTS: Individuals with DID differed from controls in CV, CT, and SA, with significantly decreased CT in the insula, anterior cingulate, and parietal regions and reduced cortical SA in temporal and orbitofrontal cortices. Abnormalities in CT and SA shared only about 3% of all significantly different cerebral surface locations and involved distinct contributions to the abnormality of CV in DID. Significant negative associations between abnormal brain morphology (SA and CV) and dissociative symptoms and early childhood traumatization (0 and 3 years of age) were found. CONCLUSIONS: In DID, neuroanatomical areas with decreased CT and SA are in different locations in the brain. As CT and SA have distinct genetic and developmental origins, our findings may indicate that different neurobiological mechanisms and environmental factors impact on cortical morphology in DID, such as early childhood traumatization.
Subject(s)
Adult Survivors of Child Adverse Events , Adverse Childhood Experiences , Cerebral Cortex/pathology , Dissociative Identity Disorder/pathology , Dissociative Identity Disorder/physiopathology , Stress Disorders, Post-Traumatic/physiopathology , Adult , Case-Control Studies , Cerebral Cortex/diagnostic imaging , Comorbidity , Dissociative Identity Disorder/diagnostic imaging , Dissociative Identity Disorder/epidemiology , Female , Humans , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Middle Aged , Stress Disorders, Post-Traumatic/epidemiologyABSTRACT
OBJECTIVE: The Trauma Model of dissociative identity disorder (DID) posits that DID is etiologically related to chronic neglect and physical and/or sexual abuse in childhood. In contrast, the Fantasy Model posits that DID can be simulated and is mediated by high suggestibility, fantasy proneness, and sociocultural influences. To date, these two models have not been jointly tested in individuals with DID in an empirical manner. METHOD: This study included matched groups [patients (n = 33) and controls (n = 32)] that were compared on psychological Trauma and Fantasy measures: diagnosed genuine DID (DID-G, n = 17), DID-simulating healthy controls (DID-S, n = 16), individuals with post-traumatic stress disorder (PTSD, n = 16), and healthy controls (HC, n = 16). Additionally, personality-state-dependent measures were obtained for DID-G and DID-S; both neutral personality states (NPS) and trauma-related personality states (TPS) were tested. CONCLUSION: For Trauma measures, the DID-G group had the highest scores, with TPS higher than NPS, followed by the PTSD, DID-S, and HC groups. The DID-G group was not more fantasy-prone or suggestible and did not generate more false memories. Malingering measures were inconclusive. Evidence consistently supported the Trauma Model of DID and challenges the core hypothesis of the Fantasy Model.
Subject(s)
Dissociative Identity Disorder/psychology , Models, Psychological , Stress Disorders, Post-Traumatic/psychology , Adolescent , Adult , Female , Humans , Middle Aged , Personality , Young AdultABSTRACT
Based on findings in traumatized animals and patients with posttraumatic stress disorder, and on traumatogenic models of complex dissociative disorders, it was hypothesized that (1) patients with complex dissociative disorders have smaller volumes of hippocampus, parahippocampal gyrus, and amygdala than normal controls, (2) these volumes are associated with severity of psychoform and somatoform dissociative symptoms, and (3) patients who recovered from dissociative identity disorder (DID) have more hippocampal volume that patients with florid DID. The preliminary findings of the study are supportive of these hypotheses. Psychotherapy for dissociative disorders may affect hippocampal volume, but longitudinal studies are required to document this potential causal relationship.
Subject(s)
Brain/pathology , Dissociative Disorders/pathology , Amygdala/pathology , Dissociative Disorders/psychology , Dissociative Disorders/therapy , Hippocampus/pathology , Humans , Parahippocampal Gyrus/pathology , Psychiatric Status Rating Scales , Somatoform Disorders/pathologyABSTRACT
Having a sense of self is an explicit and high-level functional specialization of the human brain. The anatomical localization of self-awareness and the brain mechanisms involved in consciousness were investigated by functional neuroimaging different emotional mental states of core consciousness in patients with Multiple Personality Disorder (i.e., Dissociative Identity Disorder (DID)). We demonstrate specific changes in localized brain activity consistent with their ability to generate at least two distinct mental states of self-awareness, each with its own access to autobiographical trauma-related memory. Our findings reveal the existence of different regional cerebral blood flow patterns for different senses of self. We present evidence for the medial prefrontal cortex (MPFC) and the posterior associative cortices to have an integral role in conscious experience.
