Functional Neuroimaging in Dissociative Disorders: A Systematic Review

Biological Correlates of Dissociative Disorders: A Systematic Review on Biomarkers and Trauma Connections

Pathological dissociation is characterized by disruptions in consciousness, memory, identity, perception, and affect, often linked to trauma and observed across various psychiatric conditions. Previous reviews do not fully cover key biological correlates used as biomarkers and do not clearly define the trauma-dissociation link. Therefore, this systematic review gives an overview of the studies on biomarkers research of the most relevant findings in associations between dissociative disorders and biological correlates. Additionally, it seeks to explore potential links between specific trauma types and recurrent biomarkers. A total of 123 studies were included, highlighting the role of increased prefrontal cortex activation and reduced hippocampal volume as potential biomarkers for pathological dissociation. Altered connectivity in the limbic system, frequently tied to childhood trauma, further underscores the neurobiological basis of dissociative symptoms. Biochemical and genetic studies, while promising, present inconsistent results and require further validation. This review underscores the importance of identifying reliable biomarkers to improve diagnostic accuracy, inform personalized treatment strategies, and monitor therapeutic responses. Future research should aim to unify methodologies and explore novel approaches to enhance clinical applications.

A cross-sectional survey on French psychiatrists' knowledge and perceptions of dissociative identity disorder

OBJECTIVE

The aim of this study was to determine French psychiatrists' level of general knowledge about dissociative identity disorder and to evaluate their perceptions of this condition.

METHODS

In this study, French psychiatrists were invited by e-mail to answer an online survey. The questionnaire asked about their general knowledge and perceptions of dissociative identity disorder.

RESULTS

We received 924 answers including 582 complete questionnaires. The survey revealed that almost two-thirds (60.8%) of psychiatrists working in France had never received any training on dissociative disorders and 62% had never managed patients suffering from dissociative identity disorder. Only 19.5% of them claimed to believe unreservedly in the existence of the diagnosis of dissociative identity disorder. The psychiatrists' confidence in diagnosing or treating dissociative identity disorder was low (mean confidence in diagnosis: 3.32 out of 10 (SD 1.89), mean confidence in treatment: 3.1 out of 10 (SD 1.68)). Fifty percent believed that dissociative identity disorder is an entity created by cinema, medias or social networks. Seventy-seven point seven percent thought that confusion with borderline personality disorder is possible, and 41.3% with schizophrenia.

CONCLUSION

In France, there is a lack of training and knowledge about dissociative identity disorder, as well as persistent skepticism about the validity of the diagnosis. Specific training seems essential for a better understanding of dissociative identity disorder.

Inter-identity amnesia and memory transfer in dissociative identity disorder: A systematic review with a meta-analysis

Individuals with dissociative identity disorder (DID) often report an inability to retrieve memories associated with other identities, termed inter-identity amnesia (IIA). Research investigating IIA has amassed, and interest surrounds whether objective deficits in retrieval mechanisms necessarily underlie the experience of IIA. This study conducted a systematic literature review with meta-analyses to examine current findings on IIA in DID. In particular, we explored whether DID patients' clinical reports of retrieval failure across identities were substantiated by controlled measures of memory. Nineteen empirical and four case studies informed the systematic review. The meta-analyses comprised twelve of the included studies. The systematic review findings suggested a degree of inter-identity memory transfer, a conclusion which was supported by two of the four meta-analyses. The remaining two meta-analyses evidenced patterns closer to IIA. Closer examination drew attention to methodological considerations that may limit definitive conclusions drawn from present studies. These include substantial heterogeneity between participants' scores which is masked by group statistics, a small and homogenous cumulative sample, limited research teams, and minimal domains of memory assessed. The paper urges a nuanced understanding of the phenomenon of IIA in light of current findings.

The Role of Momentary Dissociation in the Sensory Cortex: A Neurophysiological Review and its Implications for Maladaptive Daydreaming

Daydreaming, a form of spontaneous and self-generated mental process, may lead to the disintegration of attention from the immediate external environment. In extreme cases, patients may develop maladaptive daydreaming comorbid with dissociation. The examination of dissociative alterations frequently occurs within the framework of complex cognitive processes. While dissociation may be a neurological and psychological dysfunction of integration, transient dissociative occurrences, i.e., momentary dissociation may signify a dynamic interplay between attentional division and orientation within the sensory cortex. Furthermore, previous studies have recorded the interactivity of attention by stimuli onset with P3 event-related potentials and the active suppression of distractor positivity. In this context, during auditory and visual mismatch negativity, the sensory cortex may interact with attentional orientation. Additionally, distractor positivity during task-relevant stimuli may play a crucial role in predicting momentary dissociation since sensory cortices share cerebral correlates with attentional fluctuations during mental imagery. Thus, this theoretical review investigated the cerebral activities associated with attentional orientation and may be extended to mindfulness. By integrating these findings, we aim to provide a comprehensive understanding of dissociative states which may lead to a resolution for dissociative psychopathology.

Dissociative Identity Disorder: A Review of Research From 2011 to 2021

ABSTRACT

Dissociative identity disorder (DID) has historically been one of the most controversial topics in the study of psychopathology. Building on a previous review of empirical research on DID from 2000 to 2010, the present review examined DID research from 2011 to 2021. The research output included 56 case studies and 104 empirical studies. Within the empirical studies, approximately 1354 new cases of DID emerged, which resulted in an average samples of approximately 20. Reanalysis of previous samples was standard in the literature with only 40% of reported cases being new. Studies emerged from dozens of countries across the world, but the majority of cases were from Western counties, especially the United States. Diagnosis primarily relied upon validated measures, but 74% of all new cases came from six research groups. Overall, research on DID is steady but methodologically limited in ways that make generalization, especially about etiology, difficult.

Dissociative identity precipitated by emergence from general anesthesia: A case report and analytical framework

Background

Dissociative identity disorder (DID) is a complex and controversial psychiatric condition in which one person maintains at least two separate and distinct personalities. Patients with DID often report a history of childhood abuse and may have other comorbid psychiatric conditions. Psychosocial stressors may be triggers for DID inception or recurrence. While anesthetic agents, in particular ketamine, may induce a temporary dissociative state, it has not yet been reported that anesthesia can precipitate a dissociative identity.

Case report

We report a case of a woman with a history of childhood sexual abuse and past suicide attempt who experienced an episode of dissociative identity on emergence from anesthesia. The episode resolved within 90 minutes and the patient was discharged home safely on hospital day two.

Conclusion

This case adds to the literature of potentially precipitating factors of DID and we provide a unifying mechanistic hypothesis linking anesthesia to functional brain connectivity.

Multiple Personality Disorder or Dissociative Identity Disorder: Etiology, Diagnosis, and Management

Dissociative identity disorder (DID), commonly known as multiple personality disorder (MPD), is a contentious mental health condition that typically arises as a result of traumatic events to help people avoid unpleasant memories. To completely comprehend the complexity and nuance of DID, this study investigates its symptomatology, diagnostic criteria, therapeutic modalities, and historical controversies. Patients with DID frequently have two or more distinct personality identities, each with its memories, characteristics, and attributes. Ten personality disorders are listed in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), but DID, formerly known as MPD, is not one of those personality disorders. Nevertheless, myths and misunderstandings cloud our knowledge of the disease, and some critics attribute the condition's emergence to therapy rather than trauma. This study emphasizes the possibilities for recovery and fulfilling life for persons affected by DID by attempting to provide a comprehensive understanding of DID, debunk myths and misconceptions, and throw light on effective therapy methods. It accomplishes this by carefully examining the body of literature and existing studies. The DID study used a systematic strategy to obtain a thorough grasp of the causes, diagnosis, symptoms, and therapies of the disorder. It employed precise keywords and Boolean operators across four databases, prioritized current peer-reviewed English-language publications, and enforced strict exclusion standards. While admitting potential biases and limits in the databases used, the research intended to maintain methodological transparency and robustness, helping to provide an accurate and up-to-date picture of DID.

Nocturnal agitation: From sleep state dissociation to sleep-related dissociative state

Nocturnal agitation refers to a broad spectrum of symptoms from simple movements to aggressive behaviors with partial or complete loss of awareness. An accurate identification of its etiology is critical for appropriate therapeutic intervention. In children and young adults, distinguishing between non-rapid eye movement (NREM) sleep parasomnias and psychogenic non-parasomniac manifestations, a condition known as sleep-related dissociative disorder (SRDD), can be challenging. This review aims to summarize current clinical, neurophysiological, and epidemiological knowledge on NREM parasomnia and SRDD, and to present the pathophysiological hypotheses underlying these nocturnal manifestations. Sleepwalking, sleep terror and confusional arousals are the three main presentations of NREM parasomnias and share common clinical characteristics. Parasomniac episodes generally occur 30minutes to three hours after sleep-onset, they are usually short, lasting no more than few minutes and involve non-stereotyped, clumsy behaviors with frequent amnesia. The prevalence of NREM parasomnia decreases from 15-30% in children to 2-4% in adults. Parasomniac episodes are incomplete awakening from the deepest NREM sleep and are characterized by a dissociated brain activity, with a wake-like activation in motor and limbic structures and a preserved sleep in the fronto-parietal regions. SRDD is a less known condition characterized by dramatic, often very long episodes with frequent aggressive and potentially dangerous behaviors. SRDD episodes frequently occur in quiet wakefulness before falling asleep. These dissociative manifestations are frequently observed in the context of psychological trauma. The pathophysiology of SRDD is poorly understood but could involve transient changes in brain connectivity due to labile sleep-wake boundaries in predisposed individuals. We hypothesize that SRDD and NREM parasomnia are forms of sleep-related dissociative states favored by a sleep-wake state dissociation during sleep-onset and awakening process, respectively.

The integrative process promoted by EMDR in dissociative disorders: neurobiological mechanisms, psychometric tools, and intervention efficacy on the psychological impact of the COVID-19 pandemic

Dissociative disorders (DDs) are characterized by a discontinuity in the normal integration of consciousness, memory, identity, emotion, perception, bodily representation, motor control, and action. The life-threatening coronavirus disease 2019 (COVID-19) pandemic has been identified as a potentially traumatic event and may produce a wide range of mental health problems, such as depression, anxiety disorders, sleep disorders, and DD, stemming from pandemic-related events, such as sickness, isolation, losing loved ones, and fear for one's life. In our conceptual analysis, we introduce the contribution of the structural dissociation of personality (SDP) theory and polyvagal theory to the conceptualization of the COVID-19 pandemic-triggered DD and the importance of assessing perceived safety in DD through neurophysiologically informed psychometric tools. In addition, we analyzed the contribution of eye movement desensitization and reprocessing (EMDR) to the treatment of the COVID-19 pandemic-triggered DD and suggest possible neurobiological mechanisms of action of the EMDR. In particular, we propose that, through slow eye movements, the EMDR may promote an initial non-rapid-eye-movement sleep stage 1-like activity, a subsequent access to a slow-wave sleep activity, and an oxytocinergic neurotransmission that, in turn, may foster the functional coupling between paraventricular nucleus and both sympathetic and parasympathetic cardioinhibitory nuclei. Neurophysiologically informed psychometric tools for safety evaluation in DDs are discussed. Furthermore, clinical and public health implications are considered, combining the EMDR, SDP theory, and polyvagal conceptualizations in light of the potential dissociative symptomatology triggered by the COVID-19 pandemic.