Biomarkers of Pathological Dissociation: A Systematic Review

Proposition of Two Subtypes of Patients at Risk of Suicide: Pain Hypersensitive Vs. Dissociative

PURPOSE OF REVIEW

The pain-suicide relationship is one of the most debated in recent literature, but theories and clinical evidence have often reached contrasting conclusions. Through a critical overview of theoretical, meta-analytical and empirical contributions, we aimed at advancing the conversation on the pain-suicide relationship by integrating research on related concepts, specifically inflammation and dissociation, and their effects on interoceptive processes and pain perception.

RECENT FINDINGS

Ideation-to-action theories consider increased pain tolerance a key risk factor for the transition from suicidal ideation to attempt. However, several meta-analytical findings suggest that suicidal thoughts and behaviors are associated with inflammation-induced pain sensitization. On the one hand, inflammation contributes to the development and maintenance of chronic pain conditions and mood disorders, and is associated with interoceptive hypervigilance and pain hypersensitivity. Moreover, a trait of increased pain tolerance does not seem to distinguish the individuals attempting suicide among those living with suicidal thoughts. On the other, temporary hypoalgesia is often activated by dissociative experiences. Highly dissociative individuals can indeed be exposed to frequent disintegration of interoceptive processes and transitory hyposensitivity to pain. In light of this, two different patterns of responses to stress (i.e. inflammation vs. dissociation) may characterize different kinds of patients at risk of suicide, associated with specific patterns of interoceptive functioning, pain sensitivity and possibly suicidal ideation. This proposition is partially supported by neuroimaging studies on post-traumatic stress disorder and psychodynamic perspectives on neurodevelopment, as well as alternative clustering models of suicidal behavior. Theoretical, meta-analytical and neurobiological evidence highlight two opposite directions in the pain-suicide relationship: hyper- vs. hyposensitivity. Such contrasts may be explained by the existence of two tendencies in stress-response, namely inflammation and dissociation, defining two different subtypes of patients at risk of suicide. We thus propose the existence of a hypersensitive subtype, defined by underlying neuroinflammatory processes, increased vulnerability to chronic pain and mood disorders, interoceptive hypervigilance, pain hypersensitivity and potentially more persistent suicidal ideation. We further hypothesize a dissociative subtype, characterized by greater trait dissociation, vulnerability to depersonalization and derealization, frequent disintegration of interoceptive processes, transient pain hyposensitivity and abrupt peaks in suicidal ideation.

How-To Study Dissociative Symptoms in a Broad Range of Mental Disorders: A Methodological Primer

Dissociative symptoms constitute a transdiagnostic phenomenon not only characterizing dissociative disorders but also occurring across a broad range of other mental disorders such as posttraumatic stress disorder or borderline personality disorder. In the latter disorders, dissociative symptoms such as depersonalization, derealization, or gaps in awareness significantly burden patients' wellbeing and functioning. Many efforts have been undertaken to better understand these debilitating symptoms. However, empirical findings have not yet converged in many areas (e.g., considering neurobiological correlates or effects of dissociative psychopathology on treatment outcome), which might partially be due to the heterogeneity and limitations of employed methodology. Here, we critically review the current state-of-the-art methodology in dissociation research, comparing methods to assess dissociative symptoms, provoke dissociative symptoms in the laboratory, select the participant sample, and consider critical sample characteristics. Discussing the informative value and limits of various standard and novel methodological approaches, we aim to provide information and nuanced guidance for future research. By these means, we aim to raise and harmonize standards in dissociation research and enable researchers of all career stages to enter, navigate, and make a significant and lasting contribution to research on dissociative symptoms in a broad range of mental disorders, ultimately contributing to a better understanding of dissociative psychopathology.

Brain white matter structural connectivity of trauma and trauma-related dissociation disorders and symptoms

BACKGROUND

Experiencing repeated childhood traumatisation impacts brain structure and function in individuals with dissociative identity disorder (DID) and post-traumatic stress disorder (PTSD). Quantitative grey matter neuroimaging research has shown aberrant volumes in traumatised individuals, however studies examining white matter are sparse, particularly for DID. The present study aims to examine white matter alterations of people with trauma-related disorders.

METHODS

Sixty-five female participants were included in this study: 33 diagnosed with a trauma-related disorder, namely 17 with DID and 16 with PTSD, and 32 healthy control (HC) participants. All participants underwent diffusion tensor imaging (DTI) and completed dissociation and traumatisation self-report measures. White matter integrity was characterised using voxel-based analysis (VBA), with network lesion mapping used to identify the implicated grey matter end points of the VBA findings.

RESULTS

Between-group VBA comparisons showed reduced fractional anisotropy (FA) for participants with DID compared to HCs in bilateral pallidum (implicating striatal projections to pre/post central gyri), midbrain, and pontocerebellar white matter. Compared to those with PTSD, DID subjects showed increased FA in the right internal capsule and right temporal areas (predominantly implicating the inferior longitudinal fasciculus). Across DID and PTSD subjects, FA values within the aforementioned findings negatively correlated with depersonalisation, psychoform and somatoform dissociation, and/or traumatisation scores.

CONCLUSIONS

Our DTI findings indicate markedly differential white matter integrity in DID compared to PTSD and HCs. This provides valuable mechanistic insights regarding a role for aberrant white matter structural integrity in traumatised female individuals with DID.

DMN network and neurocognitive changes associated with dissociative symptoms in major depressive disorder: a research protocol

Introduction

Depression is a heterogeneous disorder with diverse clinical presentations and etiological underpinnings, necessitating the identification of distinct subtypes to enhance targeted interventions. Dissociative symptoms, commonly observed in major depressive disorder (MDD) and linked to early life trauma, may represent a unique clinical dimension associated with specific neurocognitive deficits. Although emerging research has begun to explore the role of dissociation in depression, most studies have provided only descriptive analyses, leaving the mechanistic interplay between these phenomena underexplored. The primary objective of this study is to determine whether MDD patients with prominent dissociative symptoms differ from those without such symptoms in clinical presentation, neurocognitive performance, and markers of functional connectivity. This investigation will be the first to integrate comprehensive clinical evaluations, advanced neurocognitive testing, and high-resolution brain imaging to delineate the contribution of dissociative symptoms in MDD.

Methods

We will recruit fifty participants for each of three groups: (1) depressive patients with dissociative symptoms, (2) depressive patients without dissociative symptoms, and (3) healthy controls. Diagnostic assessments will be performed using the Structured Clinical Interview for DSM-5 (SCID) alongside standardized scales for depression severity, dissociation, and childhood trauma. Neurocognitive performance will be evaluated through a battery of tests assessing memory, attention, executive function, and processing speed. Structural and functional magnetic resonance imaging (MRI) will be conducted on a 3 Tesla scanner, focusing on the connectivity of the Default Mode Network with key regions such as the orbitofrontal cortex, insula, and posterior cingulate cortex. Data analyses will employ SPM-12 and Matlab-based CONN and PRONTO tools, with multiclass Gaussian process classification applied to differentiate the three groups based on clinical, cognitive, and imaging data.

Discussion

The results of this study will introduce a novel perspective on understanding the connection between major depressive disorder and dissociation. It could also aid in pinpointing a distinct form of depression associated with dissociative symptoms and early childhood stressors.

Conclusion

Future research, aiming to forecast the response to biological and psychological interventions for depression, anticipates this subtype and provides insights.

Dissociative experiences alter resting state functional connectivity after childhood abuse

Dissociative experiences commonly occur alongside adverse childhood experiences (ACE), yet research on their neurofunctional biomarkers has overlooked their unique association with dimensions of childhood abuse and neglect. We investigated interactions between dissociative experiences and childhood abuse, anticipating anti-correlations between the right-lateralized anterior middle frontal gyrus (raMFG) and the medial temporal lobe, as well as the temporal gyri. Examining resting-state functional connectivity in 91 participants with a history of ACE, we employed seed-to-voxel analyses seeding the raMFG. Multiple linear regression and post-hoc moderation/mediation models explored interactions and individual effects of dissociation and dimensions of ACE. The Dissociative Experiences Scale (DES) and Childhood Trauma Questionnaire (CTQ) quantified dissociation and dimensions of ACE. A DES by CTQ-A (childhood abuse) interaction predicted an anti-correlation between the raMFG and right hippocampus, moderated by CTQ-A. The CTQ revealed negative connectivity between the raMFG and right anterior cingulate cortex. CTQ-N (childhood neglect) indicated that both the right supplementary motor area and right insula related positively to the raMFG. Our findings underscore a distinct neural signature of childhood abuse-related dissociative experiences, potentially linked to dissociated memories.

Dissociative episodes and concurrent heart rate in patients with PTSD - An ecological momentary assessment

Dissociative symptoms are a frequent complication in posttraumatic stress disorders affecting about a third of all PTSD patients. While theoretical models predict a physiological hypoarousal during posttraumatic dissociations, empirical evidence is lacking. We addressed this by studying spontaneously occurring dissociative symptoms and related heart rate changes in an ecological momentary assessment. Therefore, we continuously measured heart rate for five to ten days with mobile ECG in 47 female inpatients diagnosed with posttraumatic stress disorder and dissociative symptoms. During this observation period, patients tracked each dissociative event on a smartphone app and reported on symptom characteristics. Patients reported a total of 164 dissociative events. Those typically lasted <30 min and involved co-occuring depersonalization and derealization of moderate to severe intensity. Tracked symptoms correlated positively with some conventional self-reports for depersonalization and derealization. Heart rate during dissociative symptoms varied greatly between and within individuals and was on average not different from baseline assessment. There was also no significant relation between dissociation intensity and heart rate change. These results challenge the theory of reactive hypoarousal during chronic dissociation and support the view that physiological adaptation modifies in the course of posttraumatic chronification. They also highlight the individual variability of dissociative symptoms and underscore the necessity of detailed assessment for targeted therapeutic approaches.

Exploring the relationship between dissociative experiences and recovery in psychosis: cross-sectional study

AIMS AND METHOD

This study explored the association among dissociative experiences, recovery from psychosis and a range of factors relevant to psychosis and analysed whether dissociative experiences (compartmentalisation, detachment and absorption) could be used to predict specific stages of recovery. A cross-sectional design was used, and 75 individuals with psychosis were recruited from the recovery services of the Gloucestershire Health and Care NHS Foundation Trust. Five questionnaires were used - the Dissociative Experiences Scale - II (DES), Detachment and Compartmentalisation Inventory (DCI), Questionnaire about the Process of Recovery, Stages of Recovery Instrument (STORI), and Positive and Negative Syndrome Scale - and a proforma was used to collect demographic data.

RESULTS

Our findings indicated that compartmentalisation, detachment and absorption, as measured by DES and DCI, do not predict stages of recovery as measured by the STORI.

CLINICAL IMPLICATIONS

The results of this study suggest that there is no simple relationship between dissociative and psychotic symptoms. They also suggest a need to assess these symptoms separately in practice and indicate that special approaches to treatment of psychosis may be needed in cases where such symptoms have a significant role.

Dissociation As a Mechanism of Risk for Interpersonal Victimization Among Adolescent Girls

Childhood interpersonal violence exposure (IVE) is associated with repeated victimization in adolescence and adulthood. Research suggests dissociation, a psychological phenomenon characterized by alterations and disruptions to consciousness, memory, and perceptions of the environment, and out-of-body experiences, increases the risk of revictimization. Self-report data from a longitudinal study of 92 violence-exposed adolescent girls from a large, urban area were analyzed to assess whether dissociation predicts polyvictimization or exposure to multiple types of interpersonal violence across adolescence. Participants' mental and interpersonal health was assessed at four in-person laboratory visits scheduled across 3.5 years (i.e., T1-T4). IVE included direct or indirect victimization experienced at home, school, the neighborhood, or town, such as child maltreatment, domestic violence, peer victimization, dating aggression, and community violence. Polyvictimization was operationalized as a composite score of the different types of IVE endorsed by the participant or caregiver. A random-intercept cross-lagged panel model was used to test the bidirectional relationships between dissociation and polyvictimization longitudinally. Cross-lagged regressions were analyzed to determine whether dissociation and polyvictimization predicted subsequent dissociation symptoms and polyvictimization. Concurrent and previous dissociation significantly accounted for polyvictimization at T2, T3, and T4. Polyvictimization did not significantly predict future dissociation symptoms. The results from this study provide support for dissociation's unique contribution to polyvictimization among violence-exposed girls, making it an important target for clinical assessment and treatment.

Unraveling the brain dynamics of Depersonalization-Derealization Disorder: a dynamic functional network connectivity analysis

BACKGROUND

Depersonalization-Derealization Disorder (DPD), a prevalent psychiatric disorder, fundamentally disrupts self-consciousness and could significantly impact the quality of life of those affected. While existing research has provided foundational insights for this disorder, the limited exploration of brain dynamics in DPD hinders a deeper understanding of its mechanisms. It restricts the advancement of diagnosis and treatment strategies. To address this, our study aimed to explore the brain dynamics of DPD.

METHODS

In our study, we recruited 84 right-handed DPD patients and 67 healthy controls (HCs), assessing them using the Cambridge Depersonalization Scale and a subliminal self-face recognition task. We also conducted a Transcranial Direct Current Stimulation (tDCS) intervention to understand its effect on brain dynamics, evidenced by Functional Magnetic Resonance Imaging (fMRI) scans. Our data preprocessing and analysis employed techniques such as Independent Component Analysis (ICA) and Dynamic Functional Network Connectivity (dFNC) to establish a comprehensive disease atlas for DPD. We compared the brain's dynamic states between DPDs and HCs using ANACOVA tests, assessed correlations with patient experiences and symptomatology through Spearman correlation analysis, and examined the tDCS effect via paired t-tests.

RESULTS

We identified distinct brain networks corresponding to the Frontoparietal Network (FPN), the Sensorimotor Network (SMN), and the Default Mode Network (DMN) in DPD using group Independent Component Analysis (ICA). Additionally, we discovered four distinct dFNC states, with State-1 displaying significant differences between DPD and HC groups (F = 4.10, P = 0.045). Correlation analysis revealed negative associations between the dwell time of State-2 and various clinical assessment factors. Post-tDCS analysis showed a significant change in the mean dwell time for State-2 in responders (t-statistic = 4.506, P = 0.046), consistent with previous clinical assessments.

CONCLUSIONS

Our study suggests the brain dynamics of DPD could be a potential biomarker for diagnosis and symptom analysis, which potentially leads to more personalized and effective treatment strategies for DPD patients.

TRIAL REGISTRATIONS

The trial was registered at the Chinese Clinical Trial Registry on 03/01/2021 (Registration number: ChiCTR2100041741, https://www.chictr.org.cn/showproj.html?proj=66731 ) before the trial.

The nested hierarchical model of self and its non-relational vs relational posttraumatic manifestation: an fMRI meta-analysis of emotional processing

Different kinds of traumatic experiences like natural catastrophes vs. relational traumatic experiences (e.g., sex/physical abuse, interpersonal partner violence) are involved in the development of the self and PTSD psychopathological manifestations. Looking at a neuroscience approach, it has been proposed a nested hierarchical model of self, which identifies three neural-mental networks: (i) interoceptive; (ii) exteroceptive; (iii) mental. However, it is still unclear how the self and its related brain networks might be affected by non-relational vs relational traumatic experiences. Departing from this background, the current study aims at conducting a meta-analytic review of task-dependent fMRI studies (i.e., emotional processing task) among patients with PTSD due to non-relational (PTSD-NR) and relational (PTSD-R) traumatic experiences using two approaches: (i) a Bayesian network meta-analysis for a region-of-interest-based approach; (ii) a coordinated-based meta-analysis. Our findings suggested that the PTSD-NR mainly recruited areas ascribed to the mental self to process emotional stimuli. Whereas, the PTSD-R mainly activated regions associated with the intero-exteroceptive self. Accordingly, the PTSD-R compared to the PTSD-NR might not reach a higher symbolic capacity to process stimuli with an emotional valence. These results are also clinically relevant in support of the development of differential treatment approaches for non-relational vs. relational PTSD.

Psychological dissociation and temporal integration/segregation across the senses: An experimental study

There are no studies that have experimentally tested how temporal integration/segregation of sensory inputs might be linked to the emergence of dissociative experiences and alterations of emotional functioning. Thirty-six participants completed 3 sensory integration tasks. Psychometric thresholds were estimated as indexes of temporal integration/segregation processes. We collected self-report measures of pre-task trait levels of dissociation, as well as pre- post-task changes in both dissociation and emotionality. An independent sample of 21 subjects completed a control experiment administering the Attention Network Test. Results showed: (i) a significant increase of dissociative experiences after the completion of sensory integration tasks, but not after the ANT task; (ii) that subjective thresholds predicted the emergence of dissociative states; (iii) temporal integration efforts affected positive emotionality, which was explained by the extent of task-dependent dissociative states. The present findings reveal that dissociation could be understood in terms of an imbalance between "hyper-segregation" and "hyper-integration" processes.

Dissociative Symptoms in Women with Histories of Intimate Partner Victimization: A Focus on Coercive Control

Identifying and contrasting different patterns of intimate partner violence (IPV) (e.g. situational couple violence, coercive controlling violence) is useful for understanding IPV and its connections with health. Applying this approach to dissociation may be fruitful, given theoretical perspectives that predict a specific connection between coercive controlling violence and dissociative symptoms. To address this, community women with divorce histories (N = 188) completed measures to identify patterns of IPV victimization in prior relationships (no direct violence, situational couple violence, coercive controlling violence), and to quantify recent dissociative symptoms and number of depressed days, for comparison. Contrary to predictions, the predicted odds of recent dissociative symptoms did not differ between women who experienced situational couple violence versus coercive controlling violence. However, the latter group had greater odds of recent dissociative symptoms, but not depressed days, compared to women with no histories of direct violence. Further, a continuous measure of coercive control was uniquely associated with increased odds of dissociative symptoms. This study provides preliminary empirical support for a connection between coercive controlling violence and dissociative symptoms, compared to women without histories of direct violence. This deserves further attention given the strong theoretical rationale for this link, and the importance of dissociation for mental health.

Psychological Therapy for Functional Neurological Disorder: Examining Impact on Dissociation, Psychological Distress and General Functioning

Functional neurological disorder (FND) represents a broad group of motor and sensory clinical symptoms which cannot be explained by other neurological diagnoses. Dissociation is considered a key mechanism in their development and maintenance. Despite psychological therapy being the recommended choice of treatment for FND, evidence for its effectiveness is in its infancy. This study explored the dissociative profile of forty-seven patients with FND and evaluated whether individual psychological therapy improved dissociative symptoms, psychological distress and general functioning among twenty-five adults with FND. Patients completed the Multiscale Dissociation Inventory, the EuroQol five-dimensional descriptive system, the General Anxiety Disorder-7 scale and the Patient Health Questionnaire-9. Our sample showed high levels of disengagement, depersonalization and memory disturbance at baseline. Treatment was associated with significant improvements in general functioning, and symptoms of dissociation and anxiety. Improvements in dissociative experiences were found to be possibly due to reduction in anxiety. Improvements in depression were the strongest predictor of improvements in general functioning. Limitations and areas for further research are discussed.

Survival, Attachment, and Healing: An Evolutionary Lens on Interventions for Trauma-Related Dissociation

Purpose

Dissociation is a necessary part of our threat response system, common to all animal species, normally temporarily activated under conditions of extreme or inescapable threat. Pathological dissociation, however, continues to occur after the initial threat has passed, in response to reminders or inaccessibility of safety and security. Present across the spectrum of psychiatric diagnoses, recurrent dissociative symptoms are linked to severe trauma exposure, insecure attachment, treatment non-response, and maladaptive coping behaviors such as substance use, suicidality, and self-harm. However, empirical studies testing treatments specific to dissociative processes remain scarce. This narrative review summarizes existing studies and provides theoretical, neurobiological, and evolutionary perspectives on dissociative processes and treatments for pathological dissociation.

Methods

A systematic search of five databases (MEDLINE, EMBASE, APA PsycINFO, CINAHL plus, Scopus) was conducted on April 13, 2023. Peer-reviewed clinical studies with adult participants, assessing intervention effects on dissociative symptoms, were included. Results were thematically analyzed and summarized.

Results

Sixty-nine studies were identified, mainly focused on posttraumatic stress disorder, trauma-exposed populations, and borderline personality disorder. Psychotherapy was studied in 72.5% of studies; other interventions included medications and neurostimulation. The majority reported positive outcomes, despite the heterogeneous spectrum of interventions. However, treatment of dissociative symptoms was the primary objective in only a minority.

Conclusion

Pathological dissociation is a complex phenomenon involving brain and body systems designed for perceiving and responding to severe threats, requiring an individualized approach. A literature is emerging regarding potentially evidence-based treatments to help those impacted by recurrent dissociative symptoms. When contextualized within a neurobiological and evolutionary perspective, these treatments can be understood as facilitating an internal and/or relational sense of safety, resulting in symptom reduction. Further studies are needed to explore effective treatments for dissociative symptoms.

The role of the immune system in depersonalisation disorder

OBJECTIVES

Depersonalisation-derealization disorder (DPD) is a dissociative disorder that impairs cognitive function and occupational performance. Emerging evidence indicate the levels of tumour necrosis factor-α and interleukin associated with the dissociative symptoms. In this study, we aimed to explore the role of the immune system in the pathology of DPD.

METHODS

We screened the protein expression in serum samples of 30 DPD patients and 32 healthy controls. Using a mass spectrometry-based proteomic approach, we identified differential proteins that were verified in another group of 25 DPD patients and 30 healthy controls using immune assays. Finally, we performed a correlation analysis between the expression of differential proteins and clinical symptoms of patients with DPD.

RESULTS

We identified several dysregulated proteins in patients with DPD compared to HCs, including decreased levels of C-reactive protein (CRP), complement C1q subcomponent subunit B, apolipoprotein A-IV, and increased levels of alpha-1-antichymotrypsin (SERPINA3). Moreover, the expression of CRP was positively correlated with visuospatial memory and the ability to inhibit cognitive interference of DPD. The expression of SERPINA3 was positively correlated with the ability to inhibit cognitive interference and negatively correlated with the perceptual alterations of DPD.

CONCLUSIONS

The dysregulation of the immune system may be the underlying biological mechanism in DPD. And the expressions of CRP and SERPINA3 can be the potential predictors for the cognitive performance of DPD.

Inter-identity amnesia in dissociative identity disorder resolved: A behavioural and neurobiological study

INTRODUCTION

Dissociative identity disorder (DID) is characterised by, among others, subjectively reported inter-identity amnesia, reflecting compromised information transfer between dissociative identity states. Studies have found conflicting results regarding memory transfer between dissociative identity states. Here, we investigated inter-identity amnesia in individuals with DID using self-relevant, subject specific stimuli, and behavioural and neural measures.

METHODS

Data of 46 matched participants were included; 14 individuals with DID in a trauma-avoidant state, 16 trauma-avoiding DID simulators, and 16 healthy controls. Reaction times and neural activation patterns related to three types of subject specific words were acquired and statistically analysed, namely non-self-relevant trauma-related words (NSt), self-relevant trauma-related words from a trauma-avoidant identity state (St), and trauma-related words from a trauma-related identity state (XSt).

RESULTS

We found no differences in reaction times between XSt and St words and faster reaction times for XSt over NSt. Reaction times of the diagnosed DID group were the longest. Increased brain activation to XSt words was found in the frontal and parietal regions, while decreased brain activity was found in the anterior cingulate cortex in the diagnosed DID group.

DISCUSSION

The current study reproduces and amalgamates previous behavioural reports as well as brain activation patterns. Our finding of increased cognitive control over self-relevant trauma-related knowledge processing has important clinical implications and calls for the redefinition of "inter-identity amnesia" to "inter-identity avoidance".

Dissociative Symptoms and Interoceptive Integration

Dissociative symptoms and disorders of dissociation are characterised by disturbances in the experience of the self and the surrounding world, manifesting as a breakdown in the normal integration of consciousness, memory, identity, emotion, and perception. This paper aims to provide insights into dissociative symptoms from the perspective of interoception, the sense of the body's internal physiological state, adopting a transdiagnostic framework.Dissociative symptoms are associated with a blunting of autonomic reactivity and a reduction in interoceptive precision. In addition to the central function of interoception in homeostasis, afferent visceral signals and their neural and mental representation have been shown to shape emotional feeling states, support memory encoding, and contribute to self-representation. Changes in interoceptive processing and disrupted integration of interoceptive signals into wider cognition may contribute to detachment from the body and the world, blunted emotional experience, and altered subjective recall, as experienced by individuals who suffer from dissociation.A better understanding of the role of altered interoceptive integration across the symptom areas of dissociation could thus provide insights into the neurophysiological mechanisms underlying dissociative disorders. As new therapeutic approaches targeting interoceptive processing emerge, recognising the significance of interoceptive mechanisms in dissociation holds potential implications for future treatment targets.

Differential constellations of dissociative symptoms and their association with childhood trauma - a latent profile analysis

Background: While several studies documented a positive correlation between childhood maltreatment severity and dissociation severity, it is currently unknown whether specific dissociative symptoms cluster together among individuals with childhood trauma histories ranging from none to severe.Objective: We aimed to explore symptom constellations across the whole spectrum of dissociative processing from patients with severe dissociative disorders to healthy controls and relate these to maltreatment severity and sociodemographic characteristics.Methods: We employed latent profile analysis to explore symptom profiles based on five subscales, measuring absorption, depersonalization, derealization, somatoform and identity alteration, based on the 20 items of the German short version of the Dissociative Experiences Scale-II (Fragebogen zu Dissoziativen Symptomen-20) in a large aggregate sample (n = 3,128) overrepresenting patients with trauma-related disorders. We then related these profiles to maltreatment severity as measured by the five subscales of the Childhood Trauma Questionnaire as well as sociodemographic characteristics.Results: Based on the five FDS subscales, six clusters differentiated by symptom severity, but not symptom constellations, were identified. Somatoform dissociation varied in accordance with the remaining symptom clusters. The cluster with the highest overall symptom severity entailed nearly all subjects diagnosed with Dissociative Identity Disorder and was characterized by extreme levels of childhood maltreatment. Both abuse and neglect were predictive of cluster membership throughout.Conclusions: The higher the severity of dissociative processing in a cluster, the more subjects reported high severity and multiplicity of childhood maltreatment. However, some subjects remain resilient to the development of dissociative processing although they experience extreme childhood maltreatment.

On the complex relationship between resilience and hair cortisol levels in adolescence despite parental physical abuse: a fourth wave of resilience research

Introduction

To understand the family's role in adolescents' mental health development and the connection to neurodevelopmental disorders related to experienced parental physical abuse, we first explored resilience pathways longitudinally and secondly, connected the identified patterns to adolescents' hair cortisol levels that are rooted in the hypothalamic-pituitary-adrenal axis as the main stress response system and connected brain structure alterations.

Methods

We analyzed longitudinal online questionnaire data for three consecutive high school years (from seventh to ninth grade) and four survey waves from a representative sample of n = 1609 high school students in Switzerland on violence-resilience pathways. Furthermore, we collected students' hair samples from a subsample of n = 229 at survey wave 4. About 30% of the participating adolescents had been physically abused by their parents. Out of the overall sample, we drew a subsample of adolescents with parental abuse experiences (survey wave 1 n = 509; survey wave 2 n = 506; survey wave 3 n = 561; survey wave 4 n = 560).

Results

Despite the odds, about 20-30% of adolescents who have experienced parental physical abuse escaped the family violence cycle and can be called resilient. By applying a person-oriented analytical approach via latent class and transition analysis, we longitudinally identified and compared four distinct violence-resilience patterns. We identified violence resilience as a multidimensional latent construct, which includes hedonic and eudaimonic protective and risk indicators. Because resilience should not solely be operationalized based on the lack of psychopathology, our latent construct included both feeling good (hedonic indicators such as high levels of self-esteem and low levels of depression/anxiety and dissociation) and doing well (eudaimonic indicators such as high levels of self-determination and self-efficacy as well as low levels of aggression toward peers).

Discussion

The present study confirmed that higher cortisol levels significantly relate to the comorbid pattern (internalizing and externalizing symptoms), and further confirmed the presence of lasting alterations in brain structures. In this way, we corroborated the insight that when studying the resilience pathways and trajectories of abused adolescents, biological markers such as hair cortisol significantly enhance and deepen the understanding of the longitudinal mechanisms of psychological markers (e.g., self-determination, self-esteem, self-efficacy) that are commonly applied in questionnaires.

Effects of psychotherapy on brain activation during negative emotional processing in patients with posttraumatic stress disorder: a systematic review and meta-analysis

Post-traumatic stress disorder (PTSD) is a debilitating condition which has been related to problems in emotional regulation, memory and cognitive control. Psychotherapy has a non-response rate of around 50% and understanding the neurobiological working mechanisms might help improve treatment. To integrate findings from multiple smaller studies, we performed the first meta-analysis of changes in brain activation with a specific focus on emotional processing after psychotherapy in PTSD patients. We performed a meta-analysis of brain activation changes after treatment during emotional processing for PTSD with seed-based d mapping using a pre-registered protocol (PROSPERO CRD42020211039). We analyzed twelve studies with 191 PTSD patients after screening 3700 studies. We performed systematic quality assessment both for the therapeutic interventions and neuroimaging methods. Analyses were done in the full sample and in a subset of studies that reported whole-brain results. We found decreased activation after psychotherapy in the left amygdala, (para)hippocampus, medial temporal lobe, inferior frontal gyrus, ventrolateral prefrontal cortex, right pallidum, anterior cingulate cortex, bilateral putamen, and insula. Decreased activation in the left amygdala and left ventrolateral PFC was also found in eight studies that reported whole-brain findings. Results did not survive correction for multiple comparisons. There is tentative support for decreased activation in the fear and cognitive control networks during emotional processing after psychotherapy for PTSD. Future studies would benefit from adopting a larger sample size, using designs that control for confounding variables, and investigating heterogeneity in symptom profiles and treatment response.

Treatment of dissociative identity disorder: leveraging neurobiology to optimize success

INTRODUCTION

Dissociative identity disorder (DID) is a treatable mental health condition that is associated with a range of psychobiological manifestations. However, historical controversy, modern day misunderstanding, and lack of professional education have prevented accurate treatment information from reaching most clinicians and patients. These obstacles also have slowed empirical efforts to improve treatment outcomes for people with DID. Emerging neurobiological findings in DID provide essential information that can be used to improve treatment outcomes.

AREAS COVERED

In this narrative review, the authors discuss symptom characteristics of DID, including dissociative self-states. Current treatment approaches are described, focusing on empirically supported psychotherapeutic interventions for DID and pharmacological agents targeting dissociative symptoms in other conditions. Neurobiological correlates of DID are reviewed, including recent research aimed at identifying a neural signature of DID.

EXPERT OPINION

Now is the time to move beyond historical controversy and focus on improving DID treatment availability and efficacy. Neurobiological findings could optimize treatment by reducing shame, aiding assessment, providing novel interventional brain targets and guiding novel pharmacologic and psychotherapeutic interventions. The inclusion of those with lived experience in the design, planning and interpretation of research investigations is another powerful way to improve health outcomes for those with DID.

Effects of a dissociative drug on fronto-limbic resting-state functional connectivity in individuals with posttraumatic stress disorder: a randomized controlled pilot study

RATIONALE

A subanesthetic dose of ketamine, a non-competitive N-methyl-D-aspartate glutamate receptor (NMDAR) antagonist, elicits dissociation in individuals with posttraumatic stress disorder (PTSD), who also often suffer from chronic dissociative symptoms in daily life. These debilitating symptoms have not only been linked to worse PTSD trajectories, but also to increased resting-state functional connectivity (RSFC) between medial prefrontal cortex (mPFC) and amygdala, supporting the conceptualization of dissociation as emotion overmodulation. Yet, as studies were observational, causal evidence is lacking.

OBJECTIVES

The present randomized controlled pilot study examines the effect of ketamine, a dissociative drug, on RSFC between mPFC subregions and amygdala in individuals with PTSD.

METHODS

Twenty-six individuals with PTSD received either ketamine (0.5mg/kg; n = 12) or the control drug midazolam (0.045mg/kg; n = 14) during functional magnetic resonance imaging (fMRI). RSFC between amygdala and mPFC subregions, i.e., ventromedial PFC (vmPFC), dorsomedial PFC (dmPFC) and anterior-medial PFC (amPFC), was assessed at baseline and during intravenous drug infusion.

RESULTS

Contrary to pre-registered predictions, ketamine did not promote a greater increase in RSFC between amygdala and mPFC subregions from baseline to infusion compared to midazolam. Instead, ketamine elicited a stronger transient decrease in vmPFC-amygdala RSFC compared to midazolam.

CONCLUSIONS

A dissociative drug did not increase fronto-limbic RSFC in individuals with PTSD. These preliminary experimental findings contrast with prior correlative findings and call for further exploration and, potentially, a more differentiated view on the neurobiological underpinning of dissociative phenomena in PTSD.

A spontaneous dissociative episode during an EEG experiment

A depersonalization episode occurred unexpectedly during an electroencephalogram (EEG) recording for a study. Experience reports tracked the time course of this event and, in conjunction, with EEG data, were analyzed. The source activity across canonical frequency bands was analyzed across four periods ended by retrospective experience reports (depersonalization was reported in the 2nd period). Delta and theta decreases occurred across all time periods with no relation to reported events. Theta and alpha increases occurred in right secondary visual areas following depersonalization, which also coincided with surges in beta and gamma. The largest increases occurred in bilateral fronto-polar and medial prefrontal cortex, followed by inferior left lateral fronto-insula-temporal cortices and right secondary visual cortex. A high frequency functional network with a principal hub in left insula closely overlapped inferior left cortical gamma band-power increases. Bilateral frontal increases in gamma are consistent with studies of dissociation. We interpret gamma and later beta, alpha, and theta band increases as arising from the generation of visual priors, in the absence of precise visual signals, which constrain interoceptive and proprioceptive predictions to reestablish a stable sense of physiological-self. Beta showed local increases following the pattern of gamma but showed no changes in functional connectivity.

Childhood Maltreatment and Amygdala Response to Interpersonal Threat in a Transdiagnostic Adult Sample: The Role of Trait Dissociation

BACKGROUND

Childhood maltreatment (CM) confers risk for different mental disorders as well as transdiagnostic symptoms such as dissociation. Aberrant amygdala response to interpersonal threat may link CM to transdiagnostic psychopathology and has recently been shown to depend on type and developmental timing of CM experiences. Still, most studies on CM and threat-related amygdala response employ categorical disorder-specific perspectives and fail to consider type and timing of CM exposure. We aimed to investigate associations between CM, amygdala response to interpersonal threat, and dimensional psychopathological symptoms including trait dissociation in a transdiagnostic adult sample, specifically considering type, timing, and duration of CM.

METHODS

We conducted a cross-sectional neuroimaging study in 141 participants with varying levels of CM, including mostly female participants with major depressive disorder (n = 36), posttraumatic stress disorder (n = 34), and somatic symptom disorder (n = 35) and healthy volunteers (n = 36). Participants underwent functional magnetic resonance imaging during an emotional face-matching task, completed the brief German interview version of the Maltreatment and Abuse Chronology of Exposure scale, and answered self-report measures of transdiagnostic CM-related symptoms including trait dissociation. Data were analyzed using a machine learning-based model comparison procedure.

RESULTS

In our transdiagnostic sample, neither type nor timing or duration of CM predicted amygdala response to interpersonal threat. Instead, trait dissociation predicted blunted bilateral amygdala response and emerged as a possible mediator between CM and amygdala function.

CONCLUSIONS

Trait dissociation may be an important confounder in the widely documented association between CM and threat-related amygdala response, which should be considered in future longitudinal studies.

Brain activation during an emotional task in participants with PTSD and borderline and/or cluster C personality disorders

INTRODUCTION

Although comorbidity of post-traumatic stress disorder (PTSD) with borderline personality disorder (BPD) and/or cluster C personality disorders (CPD) is common, neural correlates of this comorbidity are unknown.

METHODS

We acquired functional MRI scans during an emotional face task in participants with PTSD + CPD (n = 34), PTSD + BPD (n = 24), PTSD + BPD + CPD (n = 18) and controls (n = 30). We used ANCOVAs and Bayesian analyses on specific ROIs in a fearful vs. scrambled faces contrast. We also investigated associations with clinical measures.

RESULTS

There were no robust differences in brain activation between the groups with ANCOVAs. Transdiagnostically, we found a negative association between severity of dissociation and right insula and right dmPFC activation, and emotion regulation problems with right dmPFC activation. Bayesian analyses showed credible evidence for higher activation in all ROIs in the PTSD + BPD + CPD group compared to PTSD + BPD and PTSD + CPD.

DISCUSSION

Our Bayesian and correlation analyses support new dimensional conceptualizations of personality disorders.

Assessing malingering and personality styles in dissociative identity disorder: a case study

Dissociative Identity Disorder (DID), formerly Multiple Personality Disorder, involves two or more distinct identities controlling behaviour, stemming from trauma-related dissociation. Understanding DID's cognitive, neural, and psychometric aspects remains a challenge, especially in distinguishing genuine cases from malingering. We present a case of a DID patient with nine identities, evaluated to rule out malingering. Using the Millon Index of Personality Styles, we assessed the primary and two alternate identities, revealing marked differences. High consistency scores support validity. We suggest employing personality inventories beyond symptomatology to characterise dissociative identities' consistency and adaptation styles, aiding in malingering assessments in future studies.

Serum Levels of Tumor Necrosis Factor-α and Vascular Endothelial Growth Factor in the Subtypes of Clinical High Risk Individuals: A Prospective Cohort Study

Introduction

Numerous studies have established the roles of inflammation and angioneurins in the pathogenesis of schizophrenia (SCZ). This study aimed to compare the serum levels of tumour necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF) in patients at clinical high risk (CHR) for psychosis or SCZ at baseline and one year after treatment.

Methods

A total of 289 CHR participants from the Shanghai At Risk for Psychosis Extended Program (SHARP) were tracked for a year. They were divided into two and four subtypes based on symptom severity according to the Structured Interview for Prodromal Syndromes (SIPS) and received standard medical care. At baseline and one-year follow-up, TNF-α and VEGF were detected using enzyme-linked immunosorbent assay, and pathological features were assessed using the Global Assessment of Function (GAF) score.

Results

Baseline TNF-α levels did not differ significantly, while VEGF levels were lower in patients with more severe symptoms. VEGF showed a negative correlation with negative features, both overall (r = -0.212, p = 0.010) and in the subgroup with higher positive scores (r = -0.370, p = 0.005). TNF-α was positively correlated with negative symptoms in the subgroup with higher negative scores (r = 0.352, p = 0.002). A three-way multivariate analysis of variance demonstrated that participants in Subtype 1 of positive or negative symptoms performed better than those in Subtype 2, with significant main effects and interactions of group and both cytokines.

Discussion

TNF-α and VEGF levels are higher and lower, respectively, in CHR patients with more severe clinical symptoms, particularly negative symptoms, which point to a worsening inflammatory and vascular status in the brain.

Dissociation in patients with epilepsy and functional seizures: A narrative review of the literature

Dissociation is a "disruption of the usually integrated functions of consciousness, memory, identity or perception of the environment" according to DSM-5.  It is commonly seen in psychiatric disorders including primary dissociative disorders, post-traumatic stress disorder, depression, and panic disorder. Dissociative phenomena are also described in the context of substance intoxication, sleep deprivation and medical illnesses including traumatic brain injury, migraines, and epilepsy. Patients with epilepsy have higher rates of dissociative experiences as measured on the Dissociative Experiences Scale compared to healthy controls. Ictal symptoms, especially in focal epilepsy of temporal lobe origin, may include dissociative-like experiences such as déjà vu/jamais vu, depersonalization, derealization and what has been described as a "dreamy state".  These descriptions are common in the setting of seizures that originate from mesial temporal lobe epilepsy and may involve the amygdala and hippocampus. Other ictal dissociative phenomena include autoscopy and out of body experiences, which are thought to be due to disruptions in networks responsible for the integration of one's own body and extra-personal space and involve the temporoparietal junction and posterior insula. In this narrative review, we will summarize the updated literature on dissociative experiences in epilepsy, as well as dissociative experiences in functional seizures. Using a case example, we will review the differential diagnosis of dissociative symptoms. We will also review neurobiological underpinnings of dissociative symptoms across different diagnostic entities and discuss how ictal symptoms may shed light on the neurobiology of complex mental processes including the subjective nature of consciousness and self-identity.

The temporal dynamics of dissociation: protocol for an ecological momentary assessment and laboratory study in a transdiagnostic sample

BACKGROUND

Dissociation is a ubiquitous clinical phenomenon. Dissociative disorders (DD) are primarily characterized by dissociation, and dissociative states are also a criterion for borderline personality disorder (BPD) and the dissociative subtype of post-traumatic stress disorder (PTSD). Dissociative reactions (e.g., depersonalization/derealization or gaps in awareness/memory) across diagnostic categories are believed to be affect contingent and theorized to serve affect regulation functions. What is not clear, however, is how self-reported affect and physiological reactivity unfold within dissociative episodes. To address this issue, the present project aims to investigate the hypothesis (1) whether self-reported distress (as indicated by arousal, e.g., feeling tense/agitated, and/or valence, e.g., feeling discontent/unwell) and physiological reactivity increase before dissociative episodes and (2) whether self-reported distress and physiological reactivity decrease during and after dissociative episodes in a transdiagnostic sample of patients with DD, BPD, and/or PTSD.

METHODS

We will use a smartphone application to assess affect and dissociation 12 times per day over the course of one week in everyday life. During this time, heart and respiratory rates will be remotely monitored. Afterwards, participants will report affect and dissociative states eight times in the laboratory before, during, and after the Trier Social Stress Test. During the laboratory task, we will continuously record heart rate, electrodermal activity, and respiratory rate, as well as measure blood pressure and take salivary samples to determine cortisol levels. Our hypotheses will be tested using multilevel structural equation models. Power analyses determined a sample size of 85.

DISCUSSION

The project will test key predictions of a transdiagnostic model of dissociation based on the idea that dissociative reactions are affect contingent and serve affect regulation functions. This project will not include non-clinical control participants. In addition, the assessment of dissociation is limited to pathological phenomena.

Towards a Neurophenomenological Understanding of Self-Disorder in Schizophrenia Spectrum Disorders: A Systematic Review and Synthesis of Anatomical, Physiological, and Neurocognitive Findings

The concept of anomalous self-experience, also termed Self-Disorder, has attracted both clinical and research interest, as empirical studies suggest such experiences specifically aggregate in and are a core feature of schizophrenia spectrum disorders. A comprehensive neurophenomenological understanding of Self-Disorder may improve diagnostic and therapeutic practice. This systematic review aims to evaluate anatomical, physiological, and neurocognitive correlates of Self-Disorder (SD), considered a core feature of Schizophrenia Spectrum Disorders (SSDs), towards developing a neurophenomenological understanding. A search of the PubMed database retrieved 285 articles, which were evaluated for inclusion using PRISMA guidelines. Non-experimental studies, studies with no validated measure of Self-Disorder, or those with no physiological variable were excluded. In total, 21 articles were included in the review. Findings may be interpreted in the context of triple-network theory and support a core dysfunction of signal integration within two anatomical components of the Salience Network (SN), the anterior insula and dorsal anterior cingulate cortex, which may mediate connectivity across both the Default Mode Network (DMN) and Fronto-Parietal Network (FPN). We propose a theoretical Triple-Network Model of Self-Disorder characterized by increased connectivity between the Salience Network (SN) and the DMN, increased connectivity between the SN and FPN, decreased connectivity between the DMN and FPN, and increased connectivity within both the DMN and FPN. We go on to describe translational opportunities for clinical practice and provide suggestions for future research.

A pharmacological challenge paradigm to assess neural signatures of script-elicited acute dissociation in women with post-traumatic stress disorder

BACKGROUND

There is limited experimentally controlled neuroimaging research available that could explain how dissociative states occur and which neurobiological changes are involved in acute post-traumatic dissociation.

AIMS

To test the causal hypothesis that acute dissociation is triggered bottom-up by a selective noradrenergic-mediated increase in amygdala activation during the processing of autobiographical trauma memories.

METHOD

Women with post-traumatic stress disorder (n = 47) and a history of interpersonal childhood trauma underwent a within-participant, placebo-controlled pharmacological challenge paradigm (4.0 mg reboxetine versus placebo) employing script-driven imagery (traumatic versus neutral autobiographical memory recall). Script-elicited brain activation patterns (measured via functional magnetic resonance imagery) were analysed by means of whole-brain analyses and a pre-registered region of interest (i.e. amygdala).

RESULTS

Self-reported acute dissociation increased significantly during trauma (versus neutral) recall but did not differ between pharmacological conditions. The pharmacological manipulation was also unsuccessful in eliciting increased amygdala activation following script-driven imagery in the reboxetine (versus placebo) condition. In the reboxetine condition, trauma retrieval resulted in similar activation patterns as in the placebo condition (e.g. elevated brain activation in the middle occipital gyrus and supramarginal gyrus), albeit with different peaks.

CONCLUSIONS

Current (null) findings cast doubt on the suggested role of the amygdala in subserving dissociative processing of trauma memories. Alternative pharmacological manipulation approaches (e.g. ketamine) and analysis techniques (e.g. event-related independent component analysis) might provide better insight into the spatiotemporal dynamics and network shifts involved in dissociative experiences and autobiographical trauma memory recall.

Experimental induction of peritraumatic dissociation: The role of negative affect and pain and their psychophysiological and neural correlates

While research has elucidated processes underlying dissociative symptoms in patients with posttraumatic stress disorder, little is known about the circumstances under which trauma-related dissociation initially arises. To experimentally investigate causes and concomitants of peritraumatic dissociation, we subjected sixty-nine healthy women to aversive-audiovisual and painful-electrical stimulation in a 2(aversive/neutral film) x 2(pain/no pain) within-subject design while recording psychophysiological and fMRI-BOLD responses. Afterwards, participants rated negative-affect, pain, and dissociation for each condition. Using Bayesian multilevel regression models, we examined (1) whether aversive-audiovisual and painful-electrical stimulation elicit higher dissociation-levels than control conditions and (2) whether stronger negative-affect and pain responses (operationalized via self-report, psychophysiological, and neural markers) correlate with higher dissociation-levels. Several key findings emerged: Both aversive-audiovisual and painful-electrical stimulation elicited dissociation. Dissociation was linked to higher self-reported negative-affect, but we did not find enough evidence linking it to psychophysiological and neural negative-affect markers. However, dissociation was associated with higher levels of self-reported pain, a skin-conductance-response-based pain marker, and the fMRI-BOLD-based Neurologic-Pain-Signature. Results indicate that both aversive-audiovisual and painful stimuli can independently cause dissociation. Critically, pain responses captured via self-report, psychophysiological, and neural markers were consistently linked to higher dissociation-levels suggesting a specific, evolutionary meaningful, contribution of pain to the rise of dissociation.

Association between baseline dissociation levels and stress-induced state dissociation in patients with posttraumatic-stress disorder, borderline personality disorder, and major depressive disorder

INTRODUCTION

Dissociative symptoms are highly prevalent in patients with trauma-related disorders such as borderline personality disorder (BPD) and posttraumatic-stress disorder (PTSD), and also occur in patients with depressive disorders. Acute dissociative states are theorized to be stress-related, and some individuals experience recurring patterns of dissociation. The relationship between the intensity of dissociative episodes (trait-like dissociation) and acute dissociative states, however, is incompletely understood. In the present study, we investigated how levels of baseline (trait-like) dissociation relate to changes in dissociative states during a laboratory stress induction.

METHODS

Our female sample comprised 65 patients with BPD and/or PTSD, 84 patients with major depressive disorder (MDD) and 44 non-clinical controls (NCC). Baseline dissociation was assessed at the start of the study using the Dissociation Tension Scale past week version (DSS-7). All participants underwent the Trier Social Stress Test (TSST) and a placebo version (P-TSST). Before and after the TSST or P-TSST, state dissociation was assessed using the Dissociation Tension Scale acute (DSS-4). We used structural equation models to estimate changes in state dissociation items (somatoform dissociation, derealization, depersonalization, analgesia), and to test whether these changes relate to levels of baseline dissociation.

RESULTS

We found significant increases in all state dissociation items in response to the TSST in patients with BPD and/or PTSD and patients with MDD, but not in NCCs. Increases in somatoform dissociation and derealization during the TSST were significantly related to higher levels of baseline dissociation in patients with BPD and/or PTSD, but not in patients with MDD or NCCs. Results indicate no significant changes in state dissociation during the P-TSST.

CONCLUSION

Our results replicate earlier findings that patients with BPD and/or PTSD report higher levels of stress-related state dissociation than NCC and extend them to patients with MDD. In addition, our findings indicate that baseline levels of dissociation relate to stress-induced changes in state dissociation among patients with BPD and PTSD, but not patients with MDD. In clinical applications, measures of baseline dissociation could be used to facilitate the prediction and treatment of stress-related dissociative states in patients with BPD and/or PTSD.

Brain Correlates of Eating Disorders in Response to Food Visual Stimuli: A Systematic Narrative Review of FMRI Studies

This article summarizes the results of studies in which functional magnetic resonance imaging (fMRI) was performed to investigate the neurofunctional activations involved in processing visual stimuli from food in individuals with anorexia nervosa (AN), bulimia nervosa (BN) and binge eating disorder (BED). A systematic review approach based on the PRISMA guidelines was used. Three databases-Scopus, PubMed and Web of Science (WoS)-were searched for brain correlates of each eating disorder. From an original pool of 688 articles, 30 articles were included and discussed. The selected studies did not always overlap in terms of research design and observed outcomes, but it was possible to identify some regularities that characterized each eating disorder. As if there were two complementary regulatory strategies, AN seems to be associated with general hyperactivity in brain regions involved in top-down control and emotional areas, such as the amygdala, insula and hypothalamus. The insula and striatum are hyperactive in BN patients and likely involved in abnormalities of impulsivity and emotion regulation. Finally, the temporal cortex and striatum appear to be involved in the neural correlates of BED, linking this condition to use of dissociative strategies and addictive aspects. Although further studies are needed, this review shows that there are specific activation pathways. Therefore, it is necessary to pay special attention to triggers, targets and maintenance processes in order to plan effective therapeutic interventions. Clinical implications are discussed.

Imaging dissociation in post-traumatic stress disorder

Symptom provocation paradigms have been successfully developed to identify the neural correlates associated with post-traumatic stress disorder (PTSD) symptoms, especially dissociative behaviours, but have critical limitations. Transiently stimulating the sympathetic nervous system and/or the hypothalamic-pituitary-adrenal (HPA) axis can enhance the stress response to symptom provocation and would help identify targets for personalised interventions.

Factor Structure and Clinical Correlates of The Dissociative Symptoms Scale (DSS) Korean Version Among Community Sample With Adverse Childhood Experiences

This study examined the factor structure and psychometric properties of the Dissociative Symptoms Scale (DSS) among the Korean community adult population with adverse childhood experiences (ACE). Data were drawn from community sample data sets collected from an online panel investigating the impact of ACE and ultimately consisted of data from a total of 1304 participants. A confirmatory factor analysis revealed a bi-factor model with a general factor and four sub-factors such as depersonalization/derealization, gaps in awareness and memory, sensory misperceptions, and cognitive behavioral reexperiencing, which are the four factors that correspond to the original DSS. The DSS showed good internal consistency as well as convergent validity with clinical correlates such as posttraumatic stress disorder, somatoform dissociation, and emotion dysregulation. The high-risk group with more ACE was associated with increased DSS. These findings support the multidimensionality of dissociation and the validity of Korean DSS scores in a general population sample.

A neurostructural biomarker of dissociative amnesia: a hippocampal study in dissociative identity disorder

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Psychometric properties of the dissociative subtype of posttraumatic stress disorder scale: replication and extension in two German-speaking samples

Background: The fifth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) introduced the dissociative subtype of posttraumatic stress disorder (D-PTSD). To assess this subtype, the Dissociative Subtype of PTSD Scale (DSPS), a 15-item self-report measure to identify lifetime and current dissociative symptoms of D-PTSD, was developed. However, so far, the scale has only been validated in war veterans. Moreover, criterion validity and diagnostic utility have not been examined yet.Objective: We aimed to validate the DSPS in two samples of civilian trauma-exposed German-speaking participants.Methods: In Study 1, a pre-registered online study, participants with and without PTSD symptoms (N = 558) answered questionnaires about traumatic experiences, dissociation, PTSD, depression, generalized anxiety disorder, somatic symptom disorder, alcohol use disorder, absorption, and dissociative responding to trauma-related questionnaires. In Study 2, which used secondary data of a pre-registered clinical study, participants with a PTSD diagnosis (N = 71) answered questionnaires about traumatic experiences, dissociation, PTSD, depression, generalized anxiety disorder, somatic symptom disorder, and dissociative responding to standardized trauma exposure. Moreover, PTSD, D-PTSD, and other diagnoses were assessed with structured clinical interviews.Results: Analyses confirmed a three-factor structure as well as high internal consistency, and high convergent, discriminant, and criterion validity of the DSPS. Moreover, the scale was able to identify a latent D-PTSD group and individuals with D-PTSD diagnosis.Conclusions: The DSPS constitutes a reliable and valid tool to assess D-PTSD symptoms in clinical practice and research and thereby may contribute to a better understanding of these debilitating symptoms.

Deconstructing dissociation: a triple network model of trauma-related dissociation and its subtypes

Trauma-related pathological dissociation is characterized by disruptions in one's sense of self, perceptual, and affective experience. Dissociation and its trauma-related antecedents disproportionately impact women. However, despite the gender-related prevalence and high individual and societal costs, dissociation remains widely underappreciated in clinical practice. Moreover, dissociation lacks a synthesized neurobiological model across its subtypes. Leveraging the Triple Network Model of psychopathology, we sought to parse heterogeneity in dissociative experience by examining functional connectivity of three core neurocognitive networks as related to: (1) the dimensional dissociation subtypes of depersonalization/derealization and partially-dissociated intrusions; and, (2) the diagnostic category of dissociative identity disorder (DID). Participants were 91 women with and without: a history of childhood trauma, current posttraumatic stress disorder (PTSD), and varied levels of dissociation. Participants provided clinical data about dissociation, PTSD symptoms, childhood maltreatment history, and completed a resting-state functional magnetic resonance imaging scan. We used a novel statistical approach to assess both overlapping and unique contributions of dissociation subtypes. Covarying for age, childhood maltreatment and PTSD severity, we found dissociation was linked to hyperconnectivity within central executive (CEN), default (DN), and salience networks (SN), and decreased connectivity of CEN and SN with other areas. Moreover, we isolated unique connectivity markers associated with depersonalization/derealization in CEN and DN, to partially-dissociated intrusions in CEN, and to DID in CEN. This suggests dissociation subtypes have robust functional connectivity signatures that may serve as targets for PTSD/DID treatment engagement. Our findings underscore dissociation assessment as crucial in clinical care, in particular, to reduce gender-related health disparities.

Dissociation and its biological and clinical associations in functional neurological disorder: systematic review and meta-analysis

BACKGROUND

Studies have reported elevated rates of dissociative symptoms and comorbid dissociative disorders in functional neurological disorder (FND); however, a comprehensive review is lacking.

AIMS

To systematically review the severity of dissociative symptoms and prevalence of comorbid dissociative disorders in FND and summarise their biological and clinical associations.

METHOD

We searched Embase, PsycInfo and MEDLINE up to June 2021, combining terms for FND and dissociation. Studies were eligible if reporting dissociative symptom scores or rates of comorbid dissociative disorder in FND samples. Risk of bias was appraised using modified Newcastle-Ottawa criteria. The findings were synthesised qualitatively and dissociative symptom scores were included in a meta-analysis (PROSPERO CRD42020173263).

RESULTS

Seventy-five studies were eligible (FND n = 3940; control n = 3073), most commonly prospective case-control studies (k = 54). Dissociative disorders were frequently comorbid in FND. Psychoform dissociation was elevated in FND compared with healthy (g = 0.90, 95% CI 0.66-1.14, I² = 70%) and neurological controls (g = 0.56, 95% CI 0.19-0.92, I² = 67%). Greater psychoform dissociation was observed in FND samples with seizure symptoms versus healthy controls (g = 0.94, 95% CI 0.65-1.22, I² = 42%) and FND samples with motor symptoms (g = 0.40, 95% CI -0.18 to 1.00, I² = 54%). Somatoform dissociation was elevated in FND versus healthy controls (g = 1.80, 95% CI 1.25-2.34, I² = 75%). Dissociation in FND was associated with more severe functional symptoms, worse quality of life and brain alterations.

CONCLUSIONS

Our findings highlight the potential clinical utility of assessing patients with FND for dissociative symptomatology. However, fewer studies investigated FND samples with motor symptoms and heterogeneity between studies and risk of bias were high. Rigorous investigation of the prevalence, features and mechanistic relevance of dissociation in FND is needed.

Altered frontal electroencephalography as a potential correlate of acute dissociation in dissociative disorders: novel findings from a mirror confrontation study

People suffering from chronic dissociation often experience stress and detachment during self-perception. We tested 18 people with dissociative disorders not otherwise specified (DDNOS; compared with a matched sample of 18 healthy controls) undergoing a stress-inducing facial mirror confrontation paradigm, and measured acute dissociation and frontal electroencephalography (measured with a four-channel system) per experimental condition (e.g. confrontation with negative cognition). Linear mixed models indicated a significant group×time×condition effect, with DDNOS group depicting less electroencephalography power than healthy controls at the beginning of mirror confrontation combined with negative and positive cognition. This discrepancy - most prominent in the negative condition - diminished in the second minute. Correlational analyses depicted a positive association between initial electroencephalography power and acute dissociation in the DDNOS group. These preliminary findings may indicate altered neural processing in DDNOS, but require further investigation with more precise electroencephalography measures.

Neurostructural brain imaging study of trait dissociation in healthy children

BACKGROUND

Trait dissociation has not been examined from a structural human brain mapping perspective in healthy adults or children. Non-pathological dissociation shares some features with daydreaming and mind-wandering, but also involves subtle disruptions in affect and autobiographical memory.

AIMS

To identify neurostructural biomarkers of trait dissociation in healthy children.

METHOD

Typically developing 9- to 15-year-olds (n = 180) without psychological or behavioural disorders were enrolled in the Developmental Chronnecto-Genomics (DevCoG) study of healthy brain development and completed psychological assessments of trauma exposure and dissociation, along with a structural T1-weighted magnetic resonance imaging. We conducted univariate ANCOVA generalised linear models for each region of the default mode network examining the effects of trait dissociation, including scanner site, age, gender and trauma as covariates and correcting for multiple comparison.

RESULTS

We found that the precuneus was significantly larger in children with higher levels of trait dissociation but this was not related to trauma exposure. The inferior parietal volume was smaller in children with higher levels of trauma but was not related to dissociation. No other regions of interest, including frontal and limbic structures, were significantly related to trait dissociation even before multiple comparison correction.

CONCLUSIONS

Trait dissociation reflects subtle cognitive disruptions worthy of study in healthy people and warrants study as a potential risk factor for psychopathology. This neurostructural study of trait dissociation in healthy children identified the precuneus as an essential brain region to consider in future dissociation research.

Persistent Dissociation and Its Neural Correlates in Predicting Outcomes After Trauma Exposure

OBJECTIVE

Dissociation, a disruption or discontinuity in psychological functioning, is often linked with worse psychiatric symptoms; however, the prognostic value of dissociation after trauma is inconsistent. Determining whether trauma-related dissociation is uniquely predictive of later outcomes would enable early identification of at-risk trauma populations. The authors conducted the largest prospective longitudinal biomarker study of persistent dissociation to date to determine its predictive capacity for adverse psychiatric outcomes following acute trauma.

METHODS

All data were part of the Freeze 2 data release from the Advancing Understanding of Recovery After Trauma (AURORA) study. Study participants provided self-report data about persistent derealization (N=1,464), a severe type of dissociation, and completed a functional MRI emotion reactivity task and resting-state scan 2 weeks posttrauma (N=145). Three-month follow-up reports were collected of posttraumatic stress, depression, pain, anxiety symptoms, and functional impairment.

RESULTS

Derealization was associated with increased ventromedial prefrontal cortex (vmPFC) activation in the emotion reactivity task and decreased resting-state vmPFC connectivity with the cerebellum and orbitofrontal cortex. In separate analyses, brain-based and self-report measures of persistent derealization at 2 weeks predicted worse 3-month posttraumatic stress symptoms, distinct from the effects of childhood maltreatment history and current posttraumatic stress symptoms.

CONCLUSIONS

The findings suggest that persistent derealization is both an early psychological and biological marker of worse later psychiatric outcomes. The neural correlates of trauma-related dissociation may serve as potential targets for treatment engagement to prevent posttraumatic stress disorder. These results underscore dissociation assessment as crucial following trauma exposure to identify at-risk individuals, and they highlight an unmet clinical need for tailored early interventions.

Neural correlates of acute post-traumatic dissociation: a functional neuroimaging script-driven imagery study

BACKGROUND

Current neurobiological models of post-traumatic stress disorder (PTSD) assume excessive medial frontal activation and hypoactivation of cortico-limbic regions as neural markers of post-traumatic dissociation. Script-driven imagery is an established experimental paradigm that is used to study acute dissociative reactions during trauma exposure. However, there is a scarcity of experimental research investigating neural markers of dissociation; findings from existing script-driven neuroimaging studies are inconsistent and based on small sample sizes.

AIMS

The current aim was to identify the neural correlates of acute post-traumatic dissociation by employing the script-driven imagery paradigm in combination with functional magnetic resonance imaging.

METHOD

Functional neuroimaging data was acquired in 51 female patients with PTSD with a history of interpersonal childhood trauma. Blood-oxygen-level-dependent response during the traumatic (versus neutral) autobiographical memory recall was analysed, and the derived activation clusters were correlated with dissociation measures.

RESULTS

During trauma recall, enhanced activation in the cerebellum, occipital gyri, supramarginal gyrus and amygdala was identified. None of the derived clusters correlated significantly with dissociative symptoms, although patients reported increased levels of acute dissociation following the paradigm.

CONCLUSIONS

The present study is one of the largest functional magnetic resonance imaging investigations of dissociative neural biomarkers in patients with PTSD undergoing experimentally induced trauma confrontation to elicit symptom-specific brain reactivity. In light of the current reproducibility crisis prominent in neuroimaging research owing to costly and time-consuming data acquisition, the current (null) findings highlight the difficulty of extracting reliable neurobiological biomarkers for complex subjective experiences such as dissociation.

Dissociative Symptoms and Disorders in Patients With Bipolar Disorders: A Scoping Review

Dissociative disorders are an important group of trauma-related disorders associated with significant disability. The co-occurrence of dissociative disorders (DD) and symptoms (DS) in bipolar disorder has been relatively understudied, but there is some evidence that this comorbidity may have significant mechanistic and clinical implications. This paper presents the results of a scoping review of the frequency and correlates of DS and DD in bipolar disorder. Based on the available evidence, DS/DD are more common in bipolar disorder than in healthy controls or in unipolar depression, are related to childhood trauma, and are associated with psychotic symptoms, suicide attempts, and a poorer response to treatment in patients with bipolar disorder. The implications of these findings, and possible mechanistic pathways underlying them, are discussed based on the current literature. Clinicians should be aware of the frequent occurrence of significant DS or DD when treating patients with bipolar disorder. A tentative future research agenda for this field, based on clinical, risk factor-related and neurobiological considerations, is outlined.

The Molecular Genetics of Dissociative Symptomatology: A Transdiagnostic Literature Review

Dissociative disorders are a common and frequently undiagnosed group of psychiatric disorders, characterized by disruptions in the normal integration of awareness, personality, emotion and behavior. The available evidence suggests that these disorders arise from an interaction between genetic vulnerability and stress, particularly traumatic stress, but the attention paid to the underlying genetic diatheses has been sparse. In this paper, the existing literature on the molecular genetics of dissociative disorders, as well as of clinically significant dissociative symptoms not reaching the threshold of a disorder, is reviewed comprehensively across clinical and non-clinical samples. Association studies suggest a link between dissociative symptoms and genes related to serotonergic, dopaminergic and peptidergic transmission, neural plasticity and cortisol receptor sensitivity, particularly following exposure to childhood trauma. Genome-wide association studies have identified loci of interest related to second messenger signaling and synaptic integration. Though these findings are inconsistent, they suggest biologically plausible mechanisms through which traumatic stress can lead to pathological dissociation. However, methodological concerns related to phenotype definition, study power, and correction for the confounding factors limit the value of these findings, and they require replication and extension in studies with better design.

Dissociation, trauma, and borderline personality disorder

Dissociation is a complex phenomenon, which occurs in various clinical conditions, including dissociative disorders, (complex) post-traumatic stress disorder (CPTSD, PTSD), and borderline personality disorder (BPD). Traumatic stress is considered an important risk factor, while the etiology of dissociation is still debated. Next to traumatic experiences, temperamental and neurobiological vulnerabilities seem to contribute to the development of dissociation. Stress-related dissociation is a prevalent symptom of BPD, which may interfere with psychosocial functioning and treatment outcome. More research in the field is strongly needed to improve the understanding and management of this complex phenomenon. This article collection brings together research on dissociation and trauma, with a special focus on BPD or sub-clinical expressions of BPD. In this editorial, recent conceptualizations of dissociation and relevant previous research are introduced in order to provide a framework for this novel research.

Dissociative identity state-dependent working memory in dissociative identity disorder: a controlled functional magnetic resonance imaging study

BACKGROUND

Memory function is at the core of the psychopathology of dissociative identity disorder (DID), but little is known about its psychobiological correlates.

AIMS

This study aims to investigate whether memory function in DID differs between dissociative identity states.

METHOD

Behavioural data and neural activation patterns were assessed in 92 sessions during an n-back working memory task. Participants were people with genuine diagnosed DID (n = 14), DID-simulating controls (n = 16) and a paired control group (post-traumatic stress disorder (n = 16), healthy controls (n = 16)). Both DID groups participated as authentic or simulated neutral and trauma-related identity states. Reaction times and errors of omission were analysed with repeated measures ANOVA. Working memory neural activation (main working memory and linear load) was investigated for effects of identity state, participant group and their interaction.

RESULTS

Identity state-dependent behavioural performance and neural activation was found. DID simulators made fewer errors of omission than those with genuine DID. Regarding the prefrontal parietal network, main working memory in the left frontal pole and ventrolateral prefrontal cortex (Brodmann area 44) was activated in all three simulated neutral states, and in trauma-related identity states of DID simulators, but not those with genuine DID or post-traumatic stress disorder; for linear load, trauma-related identity states of those with genuine DID did not engage the parietal regions.

CONCLUSIONS

Behavioural performance and neural activation patterns related to working memory in DID are dependent on the dissociative identities involved. The narrowed consciousness of trauma-related identity states, with a proneness to re-experiencing traumatising events, may relate to poorer working memory functioning.

Normal amygdala morphology in dissociative identity disorder

Studies investigating the structure of the amygdala in relation to dissociation in psychiatric disorders are limited and have reported normal or preserved, increased or decreased global volumes. Thus, a more detailed investigation of the amygdala is warranted. Amygdala global and subregional volumes were compared between individuals with dissociative identity disorder (DID: n = 32) and healthy controls (n = 42). Analyses of covariance did not show volumetric differences between the DID and control groups. Although several unknowns make it challenging to interpret our findings, we propose that the finding of normal amygdala volume is a genuine finding because other studies using this data-set have presented robust morphological aberrations in relation to the diagnosis of DID.