Dissociative identity disorder (DID) is a severely debilitating disorder. Despite recognition in the current and past versions of the DSM, DID remains a controversial psychiatric disorder, which ...hampers its diagnosis and treatment. Neurobiological evidence regarding the aetiology of DID supports clinical observations that it is a severe form of post-traumatic stress disorder.
The authors conducted a comprehensive meta-analysis of MRI region-of-interest and voxel-based morphometry (VBM) studies in posttraumatic stress disorder (PTSD). Because patients have high rates of ...comorbid depression, an additional objective was to compare the findings to a meta-analysis of MRI studies in depression.
The MEDLINE database was searched for studies from 1985 through 2016. A total of 113 studies met inclusion criteria and were included in an online database. Of these, 66 were selected for the region-of-interest meta-analysis and 13 for the VBM meta-analysis. The region-of-interest meta-analysis was conducted and compared with a meta-analysis of major depressive disorder. Within the region-of-interest meta-analysis, three subanalyses were conducted that included control groups with and without trauma.
In the region-of-interest meta-analysis, patients with PTSD compared with all control subjects were found to have reduced brain volume, intracranial volume, and volumes of the hippocampus, insula, and anterior cingulate. PTSD patients compared with nontraumatized or traumatized control subjects showed similar changes. Traumatized compared with nontraumatized control subjects showed smaller volumes of the hippocampus bilaterally. For all regions, pooled effect sizes (Hedges' g) varied from -0.84 to 0.43, and number of studies from three to 41. The VBM meta-analysis revealed prominent volumetric reductions in the medial prefrontal cortex, including the anterior cingulate. Compared with region-of-interest data from patients with major depressive disorder, those with PTSD had reduced total brain volume, and both disorders were associated with reduced hippocampal volume.
The meta-analyses revealed structural brain abnormalities associated with PTSD and trauma and suggest that global brain volume reductions distinguish PTSD from major depression.
•Neurofunctional biomarkers of pathological dissociation are the dorsomedial and dorsolateral prefrontal cortex, bilateral superior frontal regions, (anterior) cingulate, posterior association areas ...and basal ganglia.•Neurostructural biomarkers of pathological dissociation are decreased hippocampal volume, basal ganglia volume and thalamus volume.•As psychobiological markers for pathological dissociation increased oxytocin and prolactin and decreased tumor necrosis factor alpha (TNF-α) are proposed.•No clear directional effects were found for psychophysiological and genetic biomarkers in relation to pathological dissociation.
Pathological dissociation is a severe, debilitating and transdiagnostic psychiatric symptom. This review identifies biomarkers of pathological dissociation in a transdiagnostic manner to recommend the most promising research and treatment pathways in support of the precision medicine framework. A total of 205 unique studies that met inclusion criteria were included. Studies were divided into four biomarker categories, namely neuroimaging, psychobiological, psychophysiological and genetic biomarkers. The dorsomedial and dorsolateral prefrontal cortex, bilateral superior frontal regions, (anterior) cingulate, posterior association areas and basal ganglia are identified as neurofunctional biomarkers of pathological dissociation and decreased hippocampal, basal ganglia and thalamic volumes as neurostructural biomarkers. Increased oxytocin and prolactin and decreased tumor necrosis factor alpha (TNF-α) are identified as psychobiological markers. Psychophysiological biomarkers, including blood pressure, heart rate and skin conductance, were inconclusive. For the genetic biomarker category studies related to dissociation were limited and no clear directionality of effect was found to warrant identification of a genetic biomarker. Recommendations for future research pathways and possible clinical applicability are provided.
A diagnosis of dissociative identity disorder (DID) is controversial and prone to under- and misdiagnosis. From the moment of seeking treatment for symptoms to the time of an accurate diagnosis of ...DID individuals received an average of four prior other diagnoses and spent 7 years, with reports of up to 12 years, in mental health services.
To investigate whether data-driven pattern recognition methodologies applied to structural brain images can provide biomarkers to aid DID diagnosis.
Structural brain images of 75 participants were included: 32 female individuals with DID and 43 matched healthy controls. Individuals with DID were recruited from psychiatry and psychotherapy out-patient clinics. Probabilistic pattern classifiers were trained to discriminate cohorts based on measures of brain morphology.
The pattern classifiers were able to accurately discriminate between individuals with DID and healthy controls with high sensitivity (72%) and specificity (74%) on the basis of brain structure. These findings provide evidence for a biological basis for distinguishing between DID-affected and healthy individuals.
We propose a pattern of neuroimaging biomarkers that could be used to inform the identification of individuals with DID from healthy controls at the individual level. This is important and clinically relevant because the DID diagnosis is controversial and individuals with DID are often misdiagnosed. Ultimately, the application of pattern recognition methodologies could prevent unnecessary suffering of individuals with DID because of an earlier accurate diagnosis, which will facilitate faster and targeted interventions.
The authors declare no competing financial interests.
Little is known about the neural correlates of dissociative amnesia, a transdiagnostic symptom mostly present in the dissociative disorders and core characteristic of dissociative identity disorder ...(DID). Given the vital role of the hippocampus in memory, a prime candidate for investigation is whether total and/or subfield hippocampal volume can serve as biological markers of dissociative amnesia.
A total of 75 women, 32 with DID and 43 matched healthy controls (HC), underwent structural magnetic resonance imaging (MRI). Using Freesurfer (version 6.0), volumes were extracted for bilateral global hippocampus, cornu ammonis (CA) 1-4, the granule cell molecular layer of the dentate gyrus (GC-ML-DG), fimbria, hippocampal-amygdaloid transition area (HATA), parasubiculum, presubiculum and subiculum. Analyses of covariance showed volumetric differences between DID and HC. Partial correlations exhibited relationships between the three factors of the dissociative experience scale scores (dissociative amnesia, absorption, depersonalisation/derealisation) and traumatisation measures with hippocampal global and subfield volumes.
Hippocampal volumes were found to be smaller in DID as compared with HC in bilateral global hippocampus and bilateral CA1, right CA4, right GC-ML-DG, and left presubiculum. Dissociative amnesia was the only dissociative symptom that correlated uniquely and significantly with reduced bilateral hippocampal CA1 subfield volumes. Regarding traumatisation, only emotional neglect correlated negatively with bilateral global hippocampus, bilateral CA1, CA4 and GC-ML-DG, and right CA3.
We propose decreased CA1 volume as a biomarker for dissociative amnesia. We also propose that traumatisation, specifically emotional neglect, is interlinked with dissociative amnesia in having a detrimental effect on hippocampal volume.
Previous research investigating structural neurodevelopmental alterations in individuals who were born very preterm demonstrated a complex pattern of grey matter changes that defy straightforward ...summary. Here we addressed this problem by characterising volumetric brain alterations in individuals who were born very preterm from adolescence to adulthood at three hierarchically related levels - global, modular and regional. We demarcated structural components that were either particularly resilient or vulnerable to the impact of very preterm birth. We showed that individuals who were born very preterm had smaller global grey matter volume compared to controls, with subcortical and medial temporal regions being particularly affected. Conversely, frontal and lateral parieto-temporal cortices were relatively resilient to the effects of very preterm birth, possibly indicating compensatory mechanisms. Exploratory analyses supported this hypothesis by showing a stronger association between lateral parieto-temporal volume and IQ in the very preterm group compared to controls. We then related these alterations to brain maturation processes. Very preterm individuals exhibited a higher maturation index compared to controls, indicating accelerated brain maturation and this was specifically associated with younger gestational age. We discuss how the findings of accelerated maturation might be reconciled with evidence of delayed maturation at earlier stages of development.
•Hierarchically related structural brain alterations in very preterm individuals span adolescence and adulthood.•Structural volumetric components that showed resiliency in very preterm individuals were associated with higher IQ.•Very preterm individuals showed accelerated brain maturation compared to a large dataset of term-born controls.
In accordance with the Theory of Structural Dissociation of the Personality (TSDP), studies of dissociative identity disorder (DID) have documented that two prototypical dissociative subsystems of ...the personality, the "Emotional Part" (EP) and the "Apparently Normal Part" (ANP), have different biopsychosocial reactions to supraliminal and subliminal trauma-related cues and that these reactions cannot be mimicked by fantasy prone healthy controls nor by actors.
Arterial spin labeling perfusion MRI was used to test the hypotheses that ANP and EP in DID have different perfusion patterns in response to rest instructions, and that perfusion is different in actors who were instructed to simulate ANP and EP. In a follow-up study, regional cerebral blood flow of DID patients was compared with the activation pattern of healthy non-simulating controls.
Compared to EP, ANP showed elevated perfusion in bilateral thalamus. Compared to ANP, EP had increased perfusion in the dorsomedial prefrontal cortex, primary somatosensory cortex, and motor-related areas. Perfusion patterns for simulated ANP and EP were different. Fitting their reported role-play strategies, the actors activated brain structures involved in visual mental imagery and empathizing feelings. The follow-up study demonstrated elevated perfusion in the left temporal lobe in DID patients, whereas non-simulating healthy controls had increased activity in areas which mediate the mental construction of past and future episodic events.
DID involves dissociative part-dependent resting-state differences. Compared to ANP, EP activated brain structures involved in self-referencing and sensorimotor actions more. Actors had different perfusion patterns compared to genuine ANP and EP. Comparisons of neural activity for individuals with DID and non-DID simulating controls suggest that the resting-state features of ANP and EP in DID are not due to imagination. The findings are consistent with TSDP and inconsistent with the idea that DID is caused by suggestion, fantasy proneness, and role-playing.
Abstract Imaging studies in posttraumatic stress disorder (PTSD) have shown differing neural network patterns between hypo-aroused/dissociative and hyper-aroused subtypes. Since dissociative identity ...disorder (DID) involves different emotional states, this study tests whether DID fits aspects of the differing brain-activation patterns in PTSD. While brain activation was monitored using positron emission tomography, DID individuals ( n =11) and matched DID-simulating healthy controls ( n =16) underwent an autobiographic script-driven imagery paradigm in a hypo-aroused and a hyper-aroused identity state. Results were consistent with those previously found in the two PTSD subtypes for the rostral/dorsal anterior cingulate, the prefrontal cortex, and the amygdala and insula, respectively. Furthermore, the dissociative identity state uniquely activated the posterior association areas and the parahippocampal gyri, whereas the hyper-aroused identity state uniquely activated the caudate nucleus. Therefore, we proposed an extended PTSD-based neurobiological model for emotion modulation in DID: the hypo-aroused identity state activates the prefrontal cortex, cingulate, posterior association areas and parahippocampal gyri, thereby overmodulating emotion regulation; the hyper-aroused identity state activates the amygdala and insula as well as the dorsal striatum, thereby undermodulating emotion regulation. This confirms the notion that DID is related to PTSD as hypo-aroused and hyper-arousal states in DID and PTSD are similar.
Background: Two aetiology models for dissociative identity disorder (DID) have been proposed, namely a childhood Trauma Model and an iatrogenic or Fantasy model. A recent study indicated that sleep ...disturbances underlie dissociative symptomatology.
Objective: Our current study aims to test whether this finding can be replicated in an independent sample and to investigate if this finding still holds after correcting for childhood and adult traumatization. An experimental working memory task is included to investigate how sleep disturbance, traumatization, dissociation, and fantasy proneness impact cognitive functioning.
Methods: Three groups of participants were included - individuals with DID, individuals with post-traumatic stress disorder (PTSD), and matched healthy controls. Sleep disturbances were measured and compared between the groups along with measures of childhood and adult traumatization, psychoform and somatoform psychological and somatic dissociative symptoms, and fantasy proneness. Cognitive capacity was assessed using a working memory task.
Results: When controlled for traumatic experiences, sleep disturbances did not predict dissociative symptoms. When controlled for sleep disturbance and fantasy proneness, childhood traumatization did predict dissociative symptoms. Psychoform dissociative symptoms correlated with traumatic experiences more than with fantasy proneness. Working memory performance was similar among the participating groups. Propensity to fantasy did not discriminate individuals with DID and PTSD, and was a weak predictor of dissociative symptoms.
Conclusion: Whereas DID and PTSD are associated with sleep disturbances, these features do not statistically predict dissociative symptoms in these disorders when traumatic experiences are taken into account. Fantasy proneness is not excessive in DID and PTSD. Hence, we found no evidence that sleep disturbances, propensity to fantasy and abnormal working memory capacity explain dissociative symptoms in DID and PTSD. In sum, the relationship between sleep and dissociative symptoms disappeared when potentially traumatizing events were controlled for.
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