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.

Validating Dissociative Experience Scale (DES) in a Greek sample.

This study aimed to validate the Greek version of the Dissociative Experience Scale (DES). A sample of 340 psychiatric outpatients and controls was selected. Part of the sample went through a retest procedure after a two-week period. Due to the absence of equivalent tests, the Multiscale Dissociation Inventory (MDI), the Structured Clinical Interview for DSM-IV-Dissociative Disorders Revised (SCID-D-R), and the Zung Self-Rating Anxiety Scale were used. Explanatory factor analysis was performed, resulting in a 28-item scale; the analysis revealed four factors, explaining 61% of total variation: Depersonalization, Amnesia, Absorption, and Miscellaneous. Cronbach's alpha coefficient for the DES was 0.95. Intraclass correlation coefficient (ICC) of the total score between the first and second interview was 0.84. Concurrent and convergent validity, as assessed by correlations with clinical assessment used as a "gold standard," (0.77), MDI (0.96), and Zung scale (0.75) were satisfactory to excellent. The total score on the DES was significantly higher in the clinical sample than in the controls (17.8 ± 16.2 vs. 5.8 ± 7.2, p < .001), indicating high discriminant validity. After the ROC analysis was run, the best compromise between sensitivity/specificity was achieved at the value of 20. The Greek version of the DES is a reliable and valid tool suitable to assess dissociation in clinical and healthy populations.

Dissociative Experiences In Iranian Depressed Patients.

In the present study, 229 major depressive disorder (MDD) patients (57.6% female; 42.4% male) were selected by convenience sampling and examined for rate of dissociative experiences. Research tools were Dissociative Experiences Scale (DES) and demographic questionnaire. Group difference examinations were performed for gender, settlement region (place of residence), and chief complaints using standard t-test, analysis of variance, and Chi-square tests as appropriate. Ordinal regression was implemented for model building. The average age of the sample was 36.78 ± 10.73. Of which, 150 (65.5%) lived in the urban and 79 (34.5%) in the rural areas. The chief complaint of the 146 patients (63.8%) was psychiatric symptoms specific to MDD, and the remaining 83 patients (36.2%) had physical symptoms. The average DES score was 10.59 ± 13.59; and a significant mean DES score differences (P < 0.01) between patients' referred to physician for physical versus psychological complaints (physical: 23.61 ± 14.39; psychological: 3.19 ± 4.5) and geographic settlements (rural: 19.58 ± 15.13; urban: 5.86 ± 9.86) were observed. This study highlights the presence of subtype within MDD patients with significant dissociative tendencies. Given the relationship between trauma history and dissociation, this subgroup could be considered as probable cases with childhood history of abuse, lending to use dissociation as a defense mechanism. Given the evidence for promising results of trauma-focused psychotherapy in treating such patients, paying proper attention to childhood history of depression especially with somatization may minimize pain and suffering of these individuals overtime.

A correlation network analysis of dissociative experiences.

The interrelationships between the symptom domains of dissociation, such as the loss of continuity in subjective experience, the inability to access personal information, and the distortions about the perception of self and the environment, need to be better understood. In the current study, 2274 adults from Italy completed the Dissociative Experiences Scale-II (DES-II), and their responses were examined within a correlation network analysis framework. Fifteen dissociative experiences showed the strongest associations with the other dissociative experiences included in the measure, and they were selected for further analysis. A partial correlation network was calculated to reveal the associations between such experiences, and a community detection analysis was used to explore whether they formed distinct clusters in the network. Subsequently, a Bayesian network was estimated to examine the direction of the associations among the dissociative experiences, and a directed acyclic graph (DAG) was generated to estimate a potentially causal model of their relationships. The community detection analysis revealed three clusters of experiences that were conceptualized in terms of trance, experiential disconnectedness, and segregated behaviors. Dissociative amnesia was a common denominator of all the three clusters. The analysis of the DAG further suggested that dissociation can be conceptualized as a network in which dissociative experiences are layered into groups of symptoms that interact among them. Cognizance of the configuration and interactions among the dissociative domains and their related symptoms may be critical for better understanding the internal logic behind the dissociative processes and for addressing them effectively in clinical practice.

Relationship of Internet gaming disorder with dissociative experience in Italian university students.

The purpose of this study was twofold: (a) to investigate the prevalence of Internet gaming disorder (IGD) among Italian university students and (b) to explore the associations between the former and dissociative phenomena. The sample included 221 college students, 93 males and 128 females, aged between 18 and 25 (M = 21.56; SD = 1.42). They were asked to state their favourite games choice and were administered a demographic questionnaire, the APA symptom checklist based on the diagnostic criteria of IGD in the DSM-5, the Internet Gaming Disorder Scale Short Form (IGD9-SF) and the Italian version of dissociative experience scale for adolescents and young adults. The different game types used are distributed as follows: Massively Multiplayer Online Role-Playing Game (30%), flash games (26%), multiplayer games (24%), and online gambling (23%). The results of the study showed a high incidence of Internet gaming disorder risk in college students (84.61%). Specifically, our data confirmed the literature on the incidence of the male gender bias among online players (M = 28.034; SD = 2.213). Thirty-three subjects (31 male and 2 female) on 221 (14.9%) matched five or more criteria for clinical diagnosis of IGD. The data showed a positive correlation between Internet gaming disorder risk and some dissociative experiences: depersonalisation and derealisation (AbII/item6 r = .311; DD/item6 r = .322); absorption and imaginative involvement (AbII/item2 r = .319; AbII/item8 r = .403) and passive influence (PI/item3 r = .304; PI/item4 r = .366; PI/item9 r = .386). This study shedded light on psychopathological aspects that preceded the spread of IGD and encourages the implementation of a programmatic plan of preventative interventions by Italian public institutions, to prevent and tame the spreading of such addictive behaviours.

Out-of-body-induced hippocampal amnesia.

Theoretical models have suggested an association between the ongoing experience of the world from the perspective of one's own body and hippocampus-based episodic memory. This link has been supported by clinical reports of long-term episodic memory impairments in psychiatric conditions with dissociative symptoms, in which individuals feel detached from themselves as if having an out-of-body experience. Here, we introduce an experimental approach to examine the necessary role of perceiving the world from the perspective of one's own body for the successful episodic encoding of real-life events. While participants were involved in a social interaction, an out-of-body illusion was elicited, in which the sense of bodily self was displaced from the real body to the other end of the testing room. This condition was compared with a well-matched in-body illusion condition, in which the sense of bodily self was colocalized with the real body. In separate recall sessions, performed ∼1 wk later, we assessed the participants' episodic memory of these events. The results revealed an episodic recollection deficit for events encoded out-of-body compared with in-body. Functional magnetic resonance imaging indicated that this impairment was specifically associated with activity changes in the posterior hippocampus. Collectively, these findings show that efficient hippocampus-based episodic-memory encoding requires a first-person perspective of the natural spatial relationship between the body and the world. Our observations have important implications for theoretical models of episodic memory, neurocognitive models of self, embodied cognition, and clinical research into memory deficits in psychiatric disorders.

Validation of the Italian version of the dissociative experience scale for adolescents and young adults.

BACKGROUND: The Dissociative Experience Scale for adolescent (A-DES), a 30-item, multidimensional, self-administered questionnaire, was validated using a large sample of American young people sample. We reported the linguistic validation process and the metric validity of the Italian version of A-DES in the Italy. METHODS: A set of questionnaires was provided to a total of 633 participants from March 2015 to April 2016. The participants consisted of 282 boys and 351 girls, and their average age was between 18 and 24 years old. The translation process consisted of two consecutive steps: forward-backward translation and acceptability testing. The psychometric testing was applied to Italian students who were recruited from the Italian Public Schools and Universities in Sicily. Informed consent was obtained from all participants at the research. All individuals completed the A-DES. Reliability and validity were tested. RESULTS: The translated version was validated on a total of 633 Italian students. The reliability of A-DES total is .926. It is composed by 4 subscales: Dissociative amnesia, Absorption and imaginative involvement, Depersonalization and derealization, and Passive influence. The reliability of each subscale is: .756 for dissociative amnesia, .659 for absorption and imaginative involvement, .850 for depersonalization and derealization, and .743 for passive influence. CONCLUSIONS: The Italian version of the A-DES constitutes a useful instrument to measure dissociative experience in adolescents and young adults in Italy.

Gray matter volume alterations related to trait dissociation in PTSD and traumatized controls.

OBJECTIVE: This study used voxel-based morphometry (VBM) to investigate brain structural alterations related to trait dissociation and its relationship with post-traumatic stress disorder (PTSD). METHOD: Thirty-two subjects either developing (N = 15) or non-developing (N = 17) PTSD underwent MRI scanning and were assessed with the Dissociative Experience Scale (DES), subscales for pathological (DES-T) and non-pathological trait (DES-A) dissociation, and other clinical measures. Gray matter volume (GMV) was analyzed using VBM as implemented in SPM. PTSD and non-PTSD subjects were compared to assess brain alterations related to PTSD pathology, whereas correlation analyses between dissociation measures and GMV were performed on the whole sample (N = 32), irrespective of PTSD diagnosis, to identify alterations related to trait dissociation. RESULTS: As compared to traumatized controls, PTSD subjects showed reduced GMV in the prefrontal cortex, hippocampus and lingual gyrus. Correlations with dissociation measures (DES, DES-T, and DES-A) consistently showed increased GMV in the medial and lateral prefrontal, orbitofrontal, parahippocampal, temporal polar, and inferior parietal cortices. CONCLUSION: PTSD and dissociation seem to be associated with opposite volumetric patterns in the prefrontal cortex. Trait dissociation appears to involve increased GMV in prefrontal, paralimbic, and parietal cortices, with negligible differences between pathological and non-pathological dissociation.

A study of post-traumatic stress disorder in schizophrenic patients 35 years after experiencing the Tangshan earthquake.

BACKGROUND: This study aimed to investigate the relationship between dissociative experiences, post-traumatic stress disorder (PTSD), and psychiatric symptoms exhibited by schizophrenic patients 35 years after the Tangshan earthquake. METHODS: Seventy-one schizophrenic patients who had experienced the Tangshan earthquake were selected and evaluated by the Post-traumatic Dissociative Experience Questionnaire (PDEQ), thPTSD Checklist-Civilian Version (PCL-C), and the Positive and Negative Symptom Scale (PANSS). RESULTS: The score of Group B (re-experiencing symptoms) in PCL-C was significantly positively correlated with age and significantly negatively correlated with the course of schizophrenia. Both gender and marriage were significantly positively correlated with the score of PCL-C Group D (irritability symptoms caused by hyperarousal). The PDEQ score was negatively correlated with thecourse of schizophrenia and positively correlated with the presence of sleep difficulties. Significant differences were found between the PCL-C scores of the positive and negative symptoms of the three core symptom groups; the positive rate of Group B was significantly higher than that of Group D, and the positive rate of Group C was significantly higher than that of Group D. The PCL-C total score was positively correlated with the negative symptom factor score of PANSS; Group C's symptoms were significantly negativelycorrelated with the positive factor score of PNASS; andGroup D's' symptoms were significantly negatively correlated with the PANSS total score and the positive factor score. CONCLUSION: When consiering patients with schizophrenia post the Tangshan earthquake, age, gender, and marital status were all positively correlated with PTSD. The course of schizophrenia was negatively associated with PTSD and dissociative experiences. PTSD was positively correlated with the negative symptoms of schizophrenia and negatively correlated with the positive symptoms of schizophrenia. Thus, the conditions and symptoms of PTSD may interact with those of schizophrenia.

Developmental abnormalities of the brain exposed to childhood maltreatment detected by diffusion tensor imaging.

Objective: This study aimed to investigate brain developmental alterations in individuals exposed to childhood maltreatment (CM) with dissociative experiences and motor coordination symptoms using diffusion tensor imaging on a 3Tesla (3T) magnetic resonance (MR) system. Methods: Five individuals exposed to CM who manifest behavioral and developmental problems with dissociative experiences and motor coordination symptoms (age range: 14-18 years; all female), as well as seven age- and gender-matched normal control individuals, participated in the study using a 3T MR system. Diffusion characteristics, as indexed by fractional anisotropy (FA), were assessed for cerebral white matter structures. A preliminary whole brain analysis was performed complementary to an anatomically guided region of interest (ROI) analysis. Results: In individuals exposed to CM, scattered decreases in FA were detected in multiple brain regions over the frontoparietal and temporal areas in the whole brain map. ROI analysis subsequently identified significant decreases in FA (p < 0.05) in the right parietal white matter area as well as in the right prefrontal, bilateral premotor, bilateral orbitofrontal, and temporal white matter areas in CM-exposed individuals compared to that in controls. Conclusion: The observed altered diffusion characteristics indicate attendant developmental abnormalities within the white matter structures, which are associated with the observed clinical and behavioral patterns including dissociative experiences and coordination symptoms in individuals exposed to CM. The study provides objective evidence regarding the effects of CM on brain microstructure.

Fear of happiness among college students: The role of gender, childhood psychological trauma, and dissociation.

AIMS: This study aimed to evaluate the fear of happiness among college students and its relationship to gender, childhood psychological trauma, and dissociation. SETTING AND DESIGN: College students were addressed as study population, and a relational screening method was implemented. MATERIALS AND METHODS: Among 184 participants, 93 (50.5%) were women. The Fear of Happiness Scale (FHS), the Childhood Trauma Questionnaire (CTQ), and the Dissociative Experiences Scale (DES) were administered to all participants. STATISTICAL ANALYSIS USED: Mann-Whitney-U and Student's t-tests were implemented for comparison of groups. Pearson correlation and stepwise multiple regression analyses were conducted to identify associations between variables. RESULTS: There were no differences on DES, FHS, and CTQ total scores between genders. DES was associated with CTQ total scores in both genders. Women had higher scores than men on childhood emotional abuse and fear of "cheerfulness ends up with bad faith." Compared to nonmembers, female dissociative taxon members had higher scores on all childhood trauma types except sexual abuse, and on all types of fear of happiness except "good fortune ends up with disaster" which was the only type of fear significantly elevated among male dissociative taxon members. A stepwise regression analysis revealed that depersonalization, childhood emotional neglect, and physical abuse predicted fear of happiness among women which was predicted by absorption among men. CONCLUSIONS: There is a relationship between childhood psychological trauma, dissociation, and fear of happiness. Women seem to be more vulnerable in this path of obsessional thinking which affects different realms in male and female genders.

Dissociation in Psychiatric Disorders: A Meta-Analysis of Studies Using the Dissociative Experiences Scale.

OBJECTIVE: Dissociation is a complex, ubiquitous construct in psychopathology. Symptoms of dissociation are present in a variety of mental disorders and have been connected to higher burden of illness and poorer treatment response, and not only in disorders with high levels of dissociation. This meta-analysis offers a systematic and evidence-based study of the prevalence and distribution of dissociation, as assessed by the Dissociative Experiences Scale, within different categories of mental disorders, and it updates an earlier meta-analysis. METHOD: More than 1,900 original publications were screened, and 216 were included in the meta-analysis, comprising 15,219 individuals in 19 diagnostic categories. RESULTS: The largest mean dissociation scores were found in dissociative disorders (mean scores >35), followed by posttraumatic stress disorder, borderline personality disorder, and conversion disorder (mean scores >25). Somatic symptom disorder, substance-related and addictive disorders, feeding and eating disorders, schizophrenia, anxiety disorder, OCD, and most affective disorders also showed mean dissociation scores >15. Bipolar disorders yielded the lowest dissociation scores (mean score, 14.8). CONCLUSIONS: The findings underline the importance of careful psychopathological assessment of dissociative symptoms in the entire range of mental disorders.

Reviewing the Dissociative Symptoms in Patients With Schizophreniaand their Association With Positive and Negative Symptoms.

OBJECTIVE: The present study aimed to clarify dissociative symptoms in patients with schizophrenia and its association with negative and positive symptom of schizophrenia. METHODS: Based on the 4(th) edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria, 80 schizophrenic subjects were randomly selected from patients who referred to the clinics of psychiatry hospital in Kerman, Iran. Eighty non-schizophrenic patients were chosen as the control group. Both groups were evaluated for dissociation symptom using the Dissociative Experience Scale (DES). Positive and Negative Syndrome Scale (PANSS) score was also used in the case group for determination of positive and negative symptom of schizophrenia. RESULTS: The prevalence of dissociation symptom was 13% and 4% among schizophrenic and control groups, respectively (p = 0.02). In addition, there was a statistical significant association between DES score and positive symptom in schizophrenia (p = 0.02). CONCLUSION: The association between dissociative symptom and schizophrenia was significant and dissociative symptoms were associated with positive symptoms of schizophrenia. DECLARATION OF INTEREST: None.

Predictors of trait dissociation and peritraumatic dissociation induced via cold pressor.

Understanding which factors predict individual dissociative response during stressful situations is important to clarify the nature of dissociation and the mechanisms associated to its use as a coping strategy. The present study examined (1) whether experiential avoidance (EA), anxiety sensitivity (AS), depressive symptoms, and state anxiety concurrently predicted trait dissociation (TD)-absorption, amnesia, depersonalization, and total TD scores-and laboratory induced dissociation (LID); and (2) whether TD and catastrophizing predicted LID. We also examined whether catastrophizing mediated the relationships between both AS and depressive symptoms and LID. A total of 101 female undergraduate students participated in a cold pressor task, which significantly induced dissociation. Results of hierarchical regression analyses showed that AS at Time 1 (9 months before the experimental session), as well as depressive symptoms and catastrophizing at the time of the experiment (Time 2), predicted LID at Time 2. Depressive symptoms at Time 2 predicted total TD, absorption, and amnesia scores. AS at Time 1 and depressive symptoms at Time 2 predicted depersonalization. AS, depressive symptoms, and catastrophizing seem to facilitate the use of dissociative strategies by healthy individuals, even in response to non-traumatic but discomforting stress.

The Korean Version of the Adolescent Dissociative Experience Scale: Psychometric Properties and the Connection to Trauma among Korean Adolescents.

OBJECTIVE: The Adolescent Dissociative Experience Scale (A-DES) is a screening measure for dissociative experience in adolescents. The present study aimed to investigate the reliability, validity and psychometric properties of the Korean version of the Adolescent Dissociative Experience Scale. METHODS: The Korean version of the A-DES was administered to a normative group of 371 adolescents aged 12 to 18 years and a traumatized group of 33 adolescents aged 12 to 18 years with known trauma. RESULTS: The internal consistency was excellent (Cronbach's alpha=0.91) and the test-retest correlation of the A-DES was high (r=0.99). Correlation between the A-DES and other measures of dissociation was moderate (r=0.48). There were no significant age differences in mean total A-DES scores for the normative sample, or for boys or girls separately. Nor were there any significant gender differences for any age group. The mean total score of the A-DES was significantly higher in the traumatized group than in the normative group. There was a statistically significant difference between adolescents with self-reported trauma and those without a trauma history in the normative group. CONCLUSION: This study demonstrated that the Korean version of the A-DES is a reliable measure with excellent internal consistency and good stability over a 4-week test-retest interval with single factor structure. It can be used to screen for dissociative symptoms in Korean adolescents between the ages 12 and 18.