Neural Correlates of Dissociative Identity Disorder

Neural Correlates of Dissociative Identity Disorder
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Neural Correlates of Dissociative Identity Disorder
Introduction
While dissociative disorders were in the past alienated from the clinical and scientific arena. However, in the last several years, they have received a renewed interest, with investigators demonstrating their underlying neural correlates. Dissociative disorders entail transient or disruptions of otherwise integrated functions of consciousness, memory, and identity (Şar, 2017). In the past, dissociative disorders subsumed under the diagnostic construct of hysteria. Such a categorization meant that dissociative disorders were viewed as the occurrences of different constellations with unexplained medical symptoms. Dissociative disorders were also seen to lack tissue pathology to account for symptoms. One of the common dissociative disorders is dissociative identity disorder (DID). The exact causes of DID are not fully understood. Research on trauma-related pathological dissociation demonstrates that it includes a wide range of disruptions in peoples' psychological experiences (Boyer, Caplan & Edwards, 2022). Some researchers seem to suggest that DID develops as a response to severe trauma, especially in childhood. When individuals undergo a traumatic experience, pathological disassociation is a common experience. Trauma can take different forms ranging from physical, emotional, and sexual abuse, to neglect, and exposure to violence. This paper will delve into the neural correlates of DID.
The role of Childhood Trauma
Individuals who have experienced stress or trauma during childhood are vulnerable to DID. Children are not born with a sense of a unified identity. Instead, the unified identity develops as a result of numerous experiences and comes from different sources. When children are overwhelmed by life’s events, most of the parts that should be blended remain separate. Their brains have not yet developed to handle traumatic events more effectively than adults. As a result, when traumatic events occur, they will have more adverse effects than then for adults. Unlike most children who manage cohesive appreciation of themselves, a majority of severely mistreated children may undergo different phases where their memories, perception, and emotions are kept separate (Ogundele, 2018). For instance, when parents and guardians alternate between affection and mistreatment, the children may develop the ability to escape the challenges by detaching themselves from the physical environment or retreating to their minds. Each traumatic experience can generate a different identity. While childhood trauma has been pinpointed as an important contributor to DID, it is not sufficient to demonstrate the origins of the disorder (Şar, Dorahy & Krüger, 2017). Neural correlation offers more details regarding DID.
Low Volumes of Hippocampal and Amygdalar
Through neuroimaging studies, researchers have identified the areas of the brain that operate differently in DID patients. An examination of the effects of neurodevelopment can account for differences observed between a normal brain and one with DID, by considering the volumes of the hippocampal and amygdalar in the brain. The two components are critical structures in the brain’s temporal lobe and are involved in various aspects of memory and emotion processing. In particular, the hippocampal plays a major role in forming and retrieving long-term memories (Wiltgen et al., 2010). Burgess, Maguire & O'Keefe (2002) link the size of the hippocampal has been linked to cognitive abilities like learning and spatial orientation. The amygdalar is associated with processing emotions, especially fear and anxiety (Šimić et al., 2021). It plays a major role in detecting and responding to potential threats and activating the nervous system, which then prepares the body for an appropriate response. Sufficient volumes of the hippocampal and amygdalar are instrumental in maintaining a balance in cognitive and emotional processes. Reduced volumes of hippocampal and amygdalar have been associated with conditions like anxiety disorders, depression, DID and PTSD (Averill et al., 2017, Morey et al. 2012 Weissman et al., 2020).
Vermetten et al., (2006) used (Magnetic Resonance Imaging.) MRI compares hippocampal and amygdalar volumes in patients with DID and healthy individuals without any psychopathology. They hypothesized that smaller hippocampal and amygdalar volumes would be found for individuals with DID compared to healthy subjects. The MRI results demonstrated that for patients with DID, hippocampus and amygdala volumes were smaller by 19.2% and 31.6%, respectively compared to patients without DID (Vermetten et al., 2006). The difference could imply that hippocampal and amygdalar can be utilized to understand DID, given that they play a major role in long-term memory and emotions. Lower volumes of hippocampal and amygdalar would demonstrate an irregularity in the brain, which would significantly alter memory and emotions, subsequently contributing to DID. Similarly, Chalavi et al., (2015) did a study to establish the relationship between childhood trauma, and dissociative symptoms of hippocampal morphology for patients with DID and Post-Traumatic Stress Disorder (PTSD). The results demonstrated that people with DID and PSTD had smaller hippocampal volumes compared to healthy controls. Chalavi et al., (2015) further established that the degree of hippocampal abnormality was positively correlated with dissociating symptoms, suggesting that hippocampal changes could be involved in the development of dissociative symptoms for individuals with DID. In essence, low volumes of hippocampal and amygdalar will expose individuals to dissociating disorders including DID.
Cortical thickness abnormalities
In the cerebral cortex, cortical thickness implies the distance between the gray matter and the white matter. Several studies have linked cortical thickness abnormalities with DID. One of the researchers is Reinders (2018) who further examined the neurodevelopmental origins of cortical abnormalities in patients with DID. The research established that compared with the healthy controls, DID patients had reduced thickness in several parts of the brain, mostly the prefrontal cortex and temporal lobe. The results demonstrate that different factors impact cortical morphology in DID, like early childhood traumatization. Similarly, Li et al. (2022) investigated cortical thickness abnormalities in patients with PSTD. The investigators used a meta-analysis approach to identify regions in the brain that indicated significant cortical thickness for PSTD patients and healthy controls. They also considered possible factors that can alter cortical thickness like age and medication use. PSTD patients demonstrated significant cortical thickness reductions in various regions of the brain. Overall, the study demonstrates that PSTD patients have cortical thickness abnormalities in regions associated with emotional processing and memory.
While Li et al. (2022) did not directly deal with DID patients, an examination of PSTD can be critical in understanding the neural correlates of DID. PSTD and DID are distinct psychological conditions that can develop in response to trauma. PSTD occurs when individuals are exposed to traumatic events like accidents, natural disasters, or violence (Kleber, 2019). While PSTD and DID have significant differences, the cortical thickness abnormalities observed in individuals with the disorders may be related to the effects of trauma on the brain. In PSTD, trauma can disrupt neurodevelopment during the critical stages of brain development (Herringa, 2017). Trauma during childhood can interfere with neuronal connections and the formation of new ones, altering the brain structure. In the same way, children exposed to traumatic activities will have problems with their neuronal connections. Since children are no...