Dissociative Subtype Of Posttraumatic Stress Disorder Research Articles

The impact of brief intensive trauma-focused treatment for PTSD on symptoms of borderline personality disorder

ABSTRACT Background: It is generally recommended to exercise caution in applying trauma-focused treatment to individuals with posttraumatic stress disorder (PTSD) and comorbid borderline personality disorder (BPD). Objective: To investigate the effects of a brief, intensive, direct trauma-focused treatment programme for individuals with PTSD on BPD symptom severity. Methods: Individuals (n = 72) with severe PTSD (87.5% had one or more comorbidities; 52.8% fulfilled the criteria for the dissociative subtype of PTSD) due to multiple traumas (e.g. 90.3% sexual abuse) participated in an intensive eight-day trauma-focused treatment programme consisting of eye movement desensitization and reprocessing (EMDR) and prolonged exposure (PE) therapy, physical activity, and psychoeducation. Treatment did not include any form of stabilization (e.g. emotion regulation training) prior to trauma-focused therapy. Assessments took place at pre- and post-treatment (Borderline Symptom List, BSL-23; PTSD symptom severity, Clinician Administered PTSD Scale for DSM-5, CAPS-5), and across the eight treatment days (PTSD Checklist, PCL-5). Results: Treatment resulted in significant decreases of BPD symptoms (Cohen’s d = 0.70). Of the 35 patients with a positive screen for BPD at pre-treatment, 32.7% lost their positive screen at post-treatment. No adverse events nor dropouts occurred during the study time frame, and none of the patients experienced symptom deterioration in response to treatment. Conclusion: The results suggest that an intensive trauma-focused treatment is a feasible and safe treatment for PTSD patients with clinically elevated symptoms of BPD, and that BPD symptoms decrease along with the PTSD symptoms.

A Network Approach to Studying the Associations Between Posttraumatic Stress Disorder Symptoms and Dissociative Experiences

In recent years, there has been a growing recognition of a dissociative subtype of posttraumatic stress disorder (D‐PTSD), characterized by experiences of depersonalization (DP) and derealization (DR), among individuals with PTSD. Little is known, however, about how experiences of DP and/or DR are associated with the experience of other PTSD symptoms. The central aim of the present paper was to explore the associations among DP, DR, and other PTSD symptoms by means of a network analysis of cross‐sectional data for 557 participants whose overall self‐reported PTSD symptom severity warranted a probable PTSD diagnosis. Three notable findings emerged: (a) a strong association between DP and DR, (b) the identification of DP as the most central symptom in the network, and (c) the discovery that clusters of symptoms in the network were roughly consistent with DSM‐5 PTSD criteria. We discuss these findings in light of some considerations, including the nature of our sample and the limits of interpreting cross‐sectional network models.

PTSD and its dissociative subtype through the lens of the insula: Anterior and posterior insula resting-state functional connectivity and its predictive validity using machine learning.

Individuals with post-traumatic stress disorder (PTSD) typically experience states of reliving and hypervigilance; however, the dissociative subtype of PTSD (PTSD+DS) presents with additional symptoms of depersonalization and derealization. Although the insula is critical to emotion processing, its association with these contrasting symptom profiles is yet to be fully delineated. Accordingly, we investigated insula subregion resting-state functional connectivity patterns among individuals with PTSD, PTSD+DS, and healthy controls. Using SPM12 and PRONTO software, we implemented a seed-based resting-state functional connectivity approach, along with multiclass Gaussian process classification machine learning, respectively, in order to evaluate unique patterns and the predictive validity of insula subregion connectivity among individuals with PTSD (n=84), PTSD+DS (n=49), and age-matched healthy controls (n=51). Ascompared to PTSD and PTSD+DS, healthy controls showed increased right anterior and posterior insula connectivity with frontal lobe structures. By contrast, PTSD showed increased bilateral posterior insula connectivity with subcortical structures, including the periaqueductal gray. Strikingly, ascompared to PTSD and controls, PTSD+DS showed increased bilateral anterior and posterior insula connectivity with posterior cortices, including the left lingual gyrus and the left precuneus. Moreover, machine learning analyses were able to classify PTSD, PTSD+DS, and controls using insula subregion connectivity patterns with 80.4% balanced accuracy (p < .01). These findings suggest a neurobiological distinction between PTSD and its dissociative subtype with regard to insula subregion functional connectivity patterns. Furthermore, machine learning algorithms were able to utilize insula resting-state connectivity patterns to discriminate between participant groups with high predictive accuracy.

The dissociative subtype of PTSD in women with substance use disorders: Exploring symptom and exposure profiles

The dissociative subtype of posttraumatic stress disorder (PTSD) was officially introduced in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). In accordance with this new classification, prior studies using Latent Class Analysis (LCA) empirically identified a subgroup of patients that were characterized by a high severity of dissociative symptoms. Despite the high prevalence of PTSD in patients with substance use disorders (SUD), however, no LCA studies on the dissociative subtype of PTSD exist in this population so far. Therefore, the current study aimed to identify subgroups of patients with different symptom and exposure profiles in patients with SUD and PTSD. It was assumed that one symptom and exposure profile could be identified that would be characterized by higher dissociative symptoms, higher additional psychopathology and a higher burden of childhood trauma, as compared to other subgroups. In N = 258 female patients with SUD and PTSD, clinical characteristics of dissociative symptoms, PTSD severity, borderline personality disorder (BPD), depression, childhood trauma and substance abuse were assessed. To identify symptom and exposure profiles, Latent Class Analysis was applied.A three-class solution indicated the best model fit to our data. One class was characterized by a high probability of dissociative symptoms (D-PTSD class), whereas the other two classes were characterized by lower probabilities of dissociative symptoms. The D-PTSD class encompassed 18.7% of the patients. In accordance with our hypothesis, the D-PTSD class showed higher probabilities of PTSD severity, borderline personality disorder symptoms, depressive symptoms, childhood emotional and sexual abuse, childhood emotional neglect, and drug abuse. Our results indicate that the dissociative subtype of PTSD could also be identified in a sample of female patients with SUD. Patients with SUD and PTSD characterized by the dissociative subtype showed more severe psychopathological symptoms than the remaining patients, indicating enhanced clinical needs for this vulnerable group.

Exploring the mutual regulation between oxytocin and cortisol as a marker of resilience

Early trauma can increase the risk for developing posttraumatic stress disorder (PTSD) in adulthood. Early trauma has also been associated with the dysregulation between the hypothalamic-pituitary-adrenal (HPA) and oxytocin systems and may influence the co-regulation between these two systems. But whether the mutual regulation of the two systems represents a sign of resilience and/or mutual dysregulation could be a sign of vulnerability to PTSD and the dissociative subtype of PTSD (PTSD-D) is unknown. The study aims to synthesize and conduct a preliminary test of a conceptual model of the mutual regulation between these two systems as a marker of resilience. We analyzed a pilot data with 22 pregnant women in 3 groups (PTSD only, PTSD-D, and trauma-exposed resilient controls) and repeated measures of plasma oxytocin and cortisol. Oxytocin and cortisol seemed reciprocal in all three groups, but both levels were relatively high in women with PTSD-D and low in those with PTSD compared with controls. This suggests that both hormones in women with PTSD-D and PTSD only are dysregulated, but not lacking in reciprocity.

Machine learning multivariate pattern analysis predicts classification of posttraumatic stress disorder and its dissociative subtype: a multimodal neuroimaging approach.

The field of psychiatry would benefit significantly from developing objective biomarkers that could facilitate the early identification of heterogeneous subtypes of illness. Critically, although machine learning pattern recognition methods have been applied recently to predict many psychiatric disorders, these techniques have not been utilized to predict subtypes of posttraumatic stress disorder (PTSD), including the dissociative subtype of PTSD (PTSD + DS). Using Multiclass Gaussian Process Classification within PRoNTo, we examined the classification accuracy of: (i) the mean amplitude of low-frequency fluctuations (mALFF; reflecting spontaneous neural activity during rest); and (ii) seed-based amygdala complex functional connectivity within 181 participants [PTSD (n = 81); PTSD + DS (n = 49); and age-matched healthy trauma-unexposed controls (n = 51)]. We also computed mass-univariate analyses in order to observe regional group differences [false-discovery-rate (FDR)-cluster corrected p < 0.05, k = 20]. We found that extracted features could predict accurately the classification of PTSD, PTSD + DS, and healthy controls, using both resting-state mALFF (91.63% balanced accuracy, p < 0.001) and amygdala complex connectivity maps (85.00% balanced accuracy, p < 0.001). These results were replicated using independent machine learning algorithms/cross-validation procedures. Moreover, areas weighted as being most important for group classification also displayed significant group differences at the univariate level. Here, whereas the PTSD + DS group displayed increased activation within emotion regulation regions, the PTSD group showed increased activation within the amygdala, globus pallidus, and motor/somatosensory regions. The current study has significant implications for advancing machine learning applications within the field of psychiatry, as well as for developing objective biomarkers indicative of diagnostic heterogeneity.

Problems with the dissociative subtype of posttraumatic stress disorder in DSM-5

The diagnostic criteria set for posttraumatic stress disorder (PTSD) has gradually evolved from DSM-III, to DSM-IV, to DSM-5. Besides a broadening of the event criterion for PTSD, the symptom domain now involves many different brain circuits and types of symptoms, including: fear and anxiety; anger and aggression; negative cognition and mood; hypo-arousal; and dissociative symptoms. The dissociative subtype of PTSD in DSM-5 is defined by the presence of depersonalization or derealization. However, the diagnostic criteria for PTSD also include dissociative flashbacks and dissociative amnesia. If these symptoms were included in the definition of the dissociative type of PTSD in future editions of the manual, then most cases of PTSD would be dissociative in nature, and non-dissociative cases would be a minority subtype. There does not appear to be any sound conceptual reason for excluding amnesia and flashbacks from the criteria for dissociative PTSD.

Dissociative symptoms mediate the relation between PTSD symptoms and functional impairment in a sample of military members, veterans, and first responders with PTSD

ABSTRACTBackground: Posttraumatic Stress Disorder (PTSD) is associated with significant functional impairment in important areas, including interpersonal relationships and occupational or educational roles. Preliminary evidence suggests that the dissociative subtype of PTSD (PTSD+DS), characterized by marked symptoms of depersonalization and derealization, is associated with increased functional impairment and disease severity, including among military members and veterans diagnosed with PTSD. Similarly, first responders (e.g. police, fire, paramedics) have also been found to experience dissociative symptoms. Despite these findings, little work has investigated whether dissociative symptoms are related to heightened functional impairment among these populations.Objective: We examined the relation between functional impairment and symptom level variables, including dissociative symptoms of depersonalization and derealization among military members, veterans, and first responders with probable PTSD. We further investigated the hypothesis that dissociative symptoms mediate the relation between PTSD symptomatology and functional impairment.Method: Eighty-one medical charts of inpatients at a residential PTSD treatment programme were accessed via retrospective review. Sixty-two were included in the present analyses. Comparison of means on symptom measures between first responders and military members/veterans were conducted, followed by correlational and mediation analyses.Results: Compared with first responders, military members and veterans showed higher levels of derealization, functional impairment, alexithymia, anxiety, and depression. Within the total sample, dissociative symptoms emerged as the strongest correlate of functional impairment and, among the dissociative symptom clusters, derealization symptoms demonstrated the strongest relation with impairment. Mediation analyses revealed that total dissociative symptoms and derealization symptoms significantly mediated the relation between PTSD symptoms and functional impairment.Conclusions: These findings highlight the importance of assessing and treating dissociative symptoms, consistent with the dissociative subtype of PTSD, among military members, veterans, and first responders with PTSD. Successful recovery on a functional and symptomatic level may necessitate treatment of dissociative symptoms, particularly derealization.

Gestational and Postnatal Cortisol Profiles of Women With Posttraumatic Stress Disorder and the Dissociative Subtype

ObjectiveTo test the hypothesis that women with posttraumatic stress disorder (PTSD) have greater salivary cortisol levels across the diurnal curve and throughout gestation, birth, and the postpartum period than women who do not have PTSD. DesignProspective, longitudinal, biobehavioral cohort study. SettingPrenatal clinics at academic health centers in the Midwest region of the United States. ParticipantsWomen expecting their first infants who fit with one of four cohorts: a nonexposed control group, a trauma-exposed control group, a group with PTSD, and a group with the dissociative subtype of PTSD. MethodsIn the first half of pregnancy, 395 women provided three salivary cortisol specimens on a single day for diurnal data. A subsample of 111 women provided three salivary cortisol specimens per day, 12 times, from early pregnancy to 6 weeks postpartum for longitudinal data. Trauma history, PTSD, and dissociative symptoms were measured via standardized telephone diagnostic interviews with the use of validated epidemiologic measures. Generalized estimating equations were used to determine group differences. ResultsGeneralized estimating equations showed that women with the dissociative subtype of PTSD had the highest and flattest gestational cortisol level curves. The difference was greatest in early pregnancy, when participants in the dissociative subtype group had cortisol levels 8 times greater in the afternoon and 10 times greater at bedtime than those in the nonexposed control group. ConclusionWomen with the dissociative subtype of PTSD, a complex form associated with a history of childhood maltreatment, may have toxic levels of cortisol that contribute to intergenerational patterns of adverse health outcomes.

The Dissociative Subtype of Posttraumatic Stress Disorder (PTSD) Among Adolescents: Co-Occurring PTSD, Depersonalization/Derealization, and Other Dissociation Symptoms

The purpose of this study was to examine the co-occurrence of posttraumatic stress disorder (PTSD) and dissociation in a clinical sample of trauma-exposed adolescents by evaluating evidence for the depersonalization/derealization dissociative subtype of PTSD as defined by the DSM-5 and then examining a broader set of dissociation symptoms. A sample of treatment-seeking, trauma-exposed adolescents 12 to 16 years old (N= 3,081) from the National Child Traumatic Stress Network Core Data Set was used to meet the study objectives. Two models of PTSD/dissociation co-occurrence were estimated using latent class analysis, one with 2 dissociation symptoms and the other with 10 dissociation symptoms. After model selection, groups within each model were compared on demographics, trauma characteristics, and psychopathology. Model A, the depersonalization/derealization model, had 5 classes: dissociative subtype/high PTSD; high PTSD; anxious arousal; dysphoric arousal; and a low symptom/reference class. Model B, the expanded dissociation model, identified an additional class characterized by dissociative amnesia and detached arousal. These 2 models provide new information about the specific ways PTSD and dissociation co-occur and illuminate some differences between adult and adolescent trauma symptom expression. A dissociative subtype of PTSD can be distinguished from PTSD alone in adolescents, but assessing a wider range of dissociative symptoms is needed to fully characterize adolescent traumatic stress responses.

The Dissociative Subtype of Post-traumatic Stress Disorder: Research Update on Clinical and Neurobiological Features.

Recently, a dissociative subtype of post-traumatic stress disorder (PTSD) has been included in the DSM-5. This review focuses on the clinical and neurobiological features that distinguish the dissociative subtype of PTSD from non-dissociative PTSD. Clinically, the dissociative subtype of PTSD is associated with high PTSD severity, predominance of derealization and depersonalization symptoms, a more significant history of early life trauma, and higher levels of comorbid psychiatric disorders. Furthermore, PTSD patients with dissociative symptoms exhibit different psychophysiological and neural responses to the recall of traumatic memories. While individuals with non-dissociative PTSD exhibit an increased heart rate, decreased activation of prefrontal regions, and increased activation of the amygdala in response to traumatic reminders, individuals with the dissociative subtype of PTSD show an opposite pattern. It has been proposed that dissociation is a regulatory strategy to restrain extreme arousal in PTSD through hyperinhibition of limbic regions. In this research update, promises and pitfalls in current research studies on the dissociative subtype of PTSD are listed. Inclusion of the dissociative subtype of PTSD in the DSM-5 stimulates research on the prevalence, symptomatology, and neurobiology of the dissociative subtype of PTSD and poses a challenge to improve treatment outcome in PTSD patients with dissociative symptoms.

Effectiveness of trauma-focused treatment for patients with psychosis with and without the dissociative subtype of post-traumatic stress disorder.

This study presents secondary analyses of a recently published trial in which post-traumatic stress disorder (PTSD) patients with psychosis (n = 108) underwent 8 sessions of trauma-focused treatment, either prolonged exposure (PE) or eye movement desensitisation and reprocessing (EMDR) therapy. 24.1% fulfilled the criteria for the dissociative subtype, a newly introduced PTSD subtype in DSM-5. Treatment outcome was compared for patients with and without the dissociative subtype of PTSD. Patients with the dissociative subtype of PTSD showed large reductions in clinician-administered PTSD scale (CAPS) score, comparable with patients without the dissociative subtype of PTSD. It is concluded that even in a population with severe mental illness, patients with the dissociative subtype of PTSD do benefit from trauma-focused treatments without a pre-phase of emotion regulation skill training and should not be excluded from these treatments.

Validation of the factor structure of the adolescent dissociative experiences scale in a sample of trauma-exposed detained youth.

The inclusion of a dissociative subtype in the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM–5) criteria for the diagnosis of posttraumatic stress disorder (PTSD) has highlighted the need for valid and reliable measures of dissociative symptoms across developmental periods. The Adolescent Dissociative Experiences Scale (A-DES) is 1 of the few measures validated for young persons, but previous studies have yielded inconsistent results regarding its factor structure. Further, research to date on the A-DES has been based upon nonclinical samples of youth or those without a known history of trauma. To address these gaps in the literature, the present study investigated the factor structure and construct validity of the A-DES in a sample of highly trauma-exposed youth involved in the juvenile justice system. A sample of 784 youth (73.7% boys) recruited from a detention center completed self-report measures of trauma exposure and the A-DES, a subset of whom (n = 212) also completed a measure of PTSD symptoms. Confirmatory factor analyses revealed a best fitting 3-factor structure comprised of depersonalization or derealization, amnesia, and loss of conscious control, with configural and metric invariance across gender. Logistic regression analyses indicated that the depersonalization or derealization factor effectively distinguished between those youth who did and did not likely meet criteria for a diagnosis of PTSD as well as those with PTSD who did and did not likely meet criteria for the dissociative subtype. These results provide support for the multidimensionality of the construct of posttraumatic dissociation and contribute to the understanding of the dissociative subtype of PTSD among adolescents. (PsycINFO Database Record

Dissociation predicts treatment response in eye-movement desensitization and reprocessing for posttraumatic stress disorder

ABSTRACTUsing clinical data from a specialized trauma clinic, this study investigated pretreatment clinical factors predicting response to eye-movement desensitization and reprocessing (EMDR) among adult patients diagnosed with posttraumatic stress disorder (PTSD). Participants were evaluated using the Clinician-Administered PTSD Scale (CAPS), the Symptom Checklist-90–Revised, the Beck Depression Inventory, and the Dissociative Experiences Scale before treatment and were reassessed using the CAPS after treatment and at 6-month follow-up. A total of 69 patients underwent an average of 4 sessions of EMDR, and 60 (87%) completed the posttreatment evaluation, including 8 participants who terminated treatment prematurely. Intent-to-treat analysis revealed that 39 (65%) of the 60 patients were classified as responders and 21 (35%) as nonresponders when response was defined as more than a 30% decrease in total CAPS score. The nonresponders had higher levels of dissociation (depersonalization and derealization) and numbing symptoms, but other PTSD symptoms, such as avoidance, hyperarousal, and intrusion, were not significantly different. The number of psychiatric comorbidities was also associated with treatment nonresponse. The final logistic regression model yielded 2 significant variables: dissociation (p < .001) and more than 2 comorbidities compared to none (p < .05). These results indicate that complex symptom patterns in PTSD may predict treatment response and support the inclusion of the dissociative subtype of PTSD in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.

Structural brain aberrations associated with the dissociative subtype of post-traumatic stress disorder.

One factor potentially contributing to the heterogeneity of previous results on structural grey matter alterations in adult participants suffering from post-traumatic stress disorder (PTSD) is the varying levels of dissociative symptomatology. The aim of this study was therefore to test whether the recently defined dissociative subtype of PTSD characterized by symptoms of depersonalization and derealization is characterized by specific differences in volumetric brain morphology. Whole-brain MRI data were acquired for 59 patients with PTSD. Voxel-based morphometry was carried out to test for group differences between patients classified as belonging (n = 15) vs. not belonging (n = 44) to the dissociative subtype of PTSD. The correlation between dissociation (depersonalization/derealization) severity and grey matter volume was computed. Patients with PTSD classified as belonging to the dissociative subtype exhibited greater grey matter volume in the right precentral and fusiform gyri as well as less volume in the right inferior temporal gyrus. Greater dissociation severity was associated with greater volume in the right middle frontal gyrus. The results of this first whole-brain investigation of specific grey matter volume in dissociative subtype PTSD indentified structural aberrations in regions subserving the processing and regulation of emotional arousal. These might constitute characteristic biomarkers for the dissociative subtype PTSD.

The Dissociative Subtype of Posttraumatic Stress Disorder: Unique Resting-State Functional Connectivity of Basolateral and Centromedial Amygdala Complexes.

Previous studies point towards differential connectivity patterns among basolateral (BLA) and centromedial (CMA) amygdala regions in patients with posttraumatic stress disorder (PTSD) as compared with controls. Here we describe the first study to compare directly connectivity patterns of the BLA and CMA complexes between PTSD patients with and without the dissociative subtype (PTSD+DS and PTSD-DS, respectively). Amygdala connectivity to regulatory prefrontal regions and parietal regions involved in consciousness and proprioception were expected to differ between these two groups based on differential limbic regulation and behavioral symptoms. PTSD patients (n=49) with (n=13) and without (n=36) the dissociative subtype and age-matched healthy controls (n=40) underwent resting-state fMRI. Bilateral BLA and CMA connectivity patterns were compared using a seed-based approach via SPM Anatomy Toolbox. Among patients with PTSD, the PTSD+DS group exhibited greater amygdala functional connectivity to prefrontal regions involved in emotion regulation (bilateral BLA and left CMA to the middle frontal gyrus and bilateral CMA to the medial frontal gyrus) as compared with the PTSD-DS group. In addition, the PTSD+DS group showed greater amygdala connectivity to regions involved in consciousness, awareness, and proprioception-implicated in depersonalization and derealization (left BLA to superior parietal lobe and cerebellar culmen; left CMA to dorsal posterior cingulate and precuneus). Differences in amygdala complex connectivity to specific brain regions parallel the unique symptom profiles of the PTSD subgroups and point towards unique biological markers of the dissociative subtype of PTSD.

A GENOME-WIDE ASSOCIATION STUDY OF CLINICAL SYMPTOMS OF DISSOCIATION IN A TRAUMA-EXPOSED SAMPLE

Recent work suggests that a subset of individuals with posttraumatic stress disorder (PTSD) exhibit marked dissociative symptoms, as defined by derealization and depersonalization. A dissociative subtype of PTSD was added to the diagnostic criteria listed in the Diagnostic and Statistical Manual of Mental Disorders, Version 5 (DSM-5) to capture this presentation of PTSD. This study examined genetic polymorphisms for association with the symptoms that define the dissociative subtype of PTSD using a genome-wide approach. The sample comprised 484 White, non-Hispanic, trauma-exposed veterans and their partners who were assessed for lifetime PTSD and dissociation using a structured clinical interview. The prevalence of PTSD was 60.5%. Single-nucleotide polymorphisms (SNPs) from across the genome were obtained from a 2.5 million SNP array. Ten SNPs evidenced suggestive association with dissociation (P < 10(-5)). No SNPs met genome-wide significance criteria (P < 5 × 10(-8)). The peak SNP was rs263232 (β = 1.4, P = 6.12 × 10(-7)), located in the adenylyl cyclase 8 (ADCY8) gene; a second SNP in the suggestive range was rs71534169 (β = 1.63, P = 3.79 × 10(-6)), located in the dipeptidyl-peptidase 6 (DPP6) gene. ADCY8 is integral for long-term potentiation and synaptic plasticity and is implicated in fear-related learning and memory and long-term memory consolidation. DPP6 is critical for synaptic integration and excitation. These genes may exert effects on basic sensory integration and cognitive processes that underlie dissociative phenomena.

Biology Not Culture Explains Dissociation in Posttraumatic Stress Disorder

D issociative symptoms are intriguing phenomena that have often provoked significant controversy in psychiatry (1). Dissociative phenomena evoke the literature about the nature of consciousness and its disruption in psychopathology (2). The proposal of the fifth revision of the DSM to include a dissociative subtype of posttraumatic stress disorder (PTSD) (3) is an important marker of acceptance in the 21st century of the enduring significance and relevance of these dissociative mechanisms in traumatic psychopathology. It is important to acknowledge how clinical interest in dissociation was a major focus in the original formulations of traumatic neurosis and hysteria (4) but that the interest in these phenomena has waxed and waned. Recent neuroimaging studies (5) have provided substantial validity to the centrality of dissociation to the importance on the deficits of affect regulation in PTSD (6). Dissociation is of particular relevance in elucidating the complex phenomenon of numbing that is accompanied by the subjective experience of derealization and depersonalization. The accumulated evidence is that dissociation is a regulatory strategy to deal with the intense hyperarousal that PTSD sufferers experience. The study by Stein et al. (7) utilizing the World Mental Health Survey about the ubiquitous nature of the dissociative type of PTSD across this cohort is an important step forward because it highlights that these phenomena occur across diverse cultures. In particular, it addresses the debate that has existed about the cross-cultural applicability of PTSD (8). The presence of dissociative symptoms across cultures has importance in understanding the origins of dissociative phenomena and argues for further exploration of its underlying neurobiological basis. In essence, depersonalization and derealization are symptoms that reflect a significant disruption of information processing systems and are well documented in traumatized populations. These symptoms cannot simply be dismissed as culture bound phenomena that are driven by suggestion. From an etiologic perspective, the study of Stein et al. (7), by the weight of numbers, adds to a clear relationship between dissociation phenomena and the exposure to prior traumatic events, childhood adversity, and the onset of PTSD in childhood. Also, although child abuse is strongly linked to dissociation, the type of trauma is not the critical issue to a dissociative subtype of PTSD but rather it is the age of trauma exposure and the experience of repeated traumatization that are highly predictive. Victims of child abuse are particularly likely to fall into such a group because of the early age of exposure and the repeated nature of abuse that in turn leads to a further risk of traumatic exposures by lack of protective

A latent class analysis of dissociation and posttraumatic stress disorder: evidence for a dissociative subtype.

The nature of the relationship of dissociation to posttraumatic stress disorder (PTSD) is controversial and of considerable clinical and nosologic importance. To examine evidence for a dissociative subtype of PTSD and to examine its association with different types of trauma. A latent profile analysis of cross-sectional data from structured clinical interviews indexing DSM-IV symptoms of current PTSD and dissociation. The VA Boston Healthcare System and the New Mexico VA Health Care System. A total of 492 veterans and their intimate partners, all of whom had a history of trauma. Participants reported exposure to a variety of traumatic events, including combat, childhood physical and sexual abuse, partner abuse, motor vehicle accidents, and natural disasters, with most participants reporting exposure to multiple types of traumatic events. Forty-two percent of the sample met the criteria for a current diagnosis of PTSD. Item-level scores on the Clinician-Administered PTSD Scale. A latent profile analysis suggested a 3-class solution: a low PTSD severity subgroup, a high PTSD severity subgroup characterized by elevations across the 17 core symptoms of the disorder, and a small but distinctly dissociative subgroup that composed 12% of individuals with a current diagnosis of PTSD. The latter group was characterized by severe PTSD symptoms combined with marked elevations on items assessing flashbacks, derealization, and depersonalization. Individuals in this subgroup also endorsed greater exposure to childhood and adult sexual trauma compared with the other 2 groups, suggesting a possible etiologic link with the experience of repeated sexual trauma. These results support the subtype hypothesis of the association between PTSD and dissociation and suggest that dissociation is a highly salient facet of posttraumatic psychopathology in a subset of individuals with the disorder.

THE DISSOCIATIVE SUBTYPE OF PTSD: A REPLICATION AND EXTENSION

The nature of the relationship between dissociation and posttraumatic stress disorder (PTSD) has clinical and nosological importance. The aim of this study was to evaluate the evidence for a dissociative subtype of PTSD in two independent samples and to examine the pattern of personality disorder (PD) comorbidity associated with the dissociative subtype of PTSD. Latent profile analyses were conducted on PTSD and dissociation items reflecting derealization and depersonalization in two samples of archived data: Study 1 included 360 male Vietnam War Veterans with combat-related PTSD; Study 2 included 284 female Veterans and active duty service personnel with PTSD and a high base rate of exposure to sexual trauma. The latent profile analysis yielded evidence for a three-class solution in both samples: the model was defined by moderate and high PTSD classes and a class marked by high PTSD severity coupled with high levels of dissociation. Approximately 15% of the male sample and 30% of the female sample were classified into the dissociative class. Women (but not men) in the dissociative group exhibited higher levels of comorbid avoidant and borderline PD diagnoses. Results provide support for a dissociative subtype of PTSD and also suggest that dissociation may play a role in the frequent co-occurrence of PTSD and borderline PD among women. These results are pertinent to the on-going revisions to the DSM and suggest that consideration should be given to incorporating a dissociative subtype into the revised PTSD criteria.