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.

Posttraumatic cognitions predict distorted body perceptions in women with dissociative identity disorder.

BACKGROUND: Dissociative identity disorder (DID) is a psychobiological syndrome associated with a history of exposure to childhood abuse and neglect. The consequences of these traumatic events often include a profound impact on the way individuals inhabit and experience their bodies. Despite this, there is a paucity of empirical research on the subject. The aim of this study was to systematically document the occurrence of distorted body perceptions in DID and examine childhood maltreatment, posttraumatic stress disorder (PTSD) symptom severity, and posttraumatic cognitions as predictors of distorted body perceptions in DID. METHODS: Participants were adult women with histories of childhood abuse and neglect and a current DID diagnosis receiving treatment at a psychiatric care facility. Data were obtained through a battery of self-report measures, including the Body Uneasiness Test, Childhood Trauma Questionnaire, PTSD Checklist for DMS-5, and Posttraumatic Cognitions Inventory. RESULTS: A series of unpaired t-tests documented elevated levels of weight phobia, body image concerns, body avoidance, compulsive self-monitoring, and depersonalization in DID compared to published non-clinical data on the Body Uneasiness Test. A series of multiple regression models including measures of childhood trauma, PTSD symptoms, and posttraumatic cognitions demonstrated that over and above childhood trauma and PTSD symptom severity, posttraumatic cognitions significantly predicted distorted body perceptions. CONCLUSIONS: In a treatment-seeking sample of women with DID, distorted body perceptions were elevated. Furthermore, posttraumatic cognitive distortions significantly predicted distorted body perceptions when controlling for childhood maltreatment and PTSD symptom severity. This suggests that distorted cognitions are a key target for therapeutic intervention.

Large-Scale Functional Brain Network Architecture Changes Associated With Trauma-Related Dissociation.

OBJECTIVE: Dissociative experiences commonly occur in response to trauma, and while their presence strongly affects treatment approaches in posttraumatic spectrum disorders, their etiology remains poorly understood and their phenomenology incompletely characterized. Methods to reliably assess the severity of dissociation symptoms, without relying solely on self-report, would have tremendous clinical utility. Brain-based measures have the potential to augment symptom reports, although it remains unclear whether brain-based measures of dissociation are sufficiently sensitive and robust to enable individual-level estimation of dissociation severity based on brain function. The authors sought to test the robustness and sensitivity of a brain-based measure of dissociation severity. METHODS: An intrinsic network connectivity analysis was applied to functional MRI scans obtained from 65 women with histories of childhood abuse and current posttraumatic stress disorder (PTSD). The authors tested for continuous measures of trauma-related dissociation using the Multidimensional Inventory of Dissociation. Connectivity estimates were derived with a novel machine learning technique using individually defined homologous functional regions for each participant. RESULTS: The models achieved moderate ability to estimate dissociation, after controlling for childhood trauma and PTSD severity. Connections that contributed the most to the estimation mainly involved the default mode and frontoparietal control networks. By contrast, all models performed at chance levels when using a conventional group-based network parcellation. CONCLUSIONS: Trauma-related dissociative symptoms, distinct from PTSD and childhood trauma, can be estimated on the basis of network connectivity. Furthermore, between-network brain connectivity may provide an unbiased estimate of symptom severity, paving the way for more objective, clinically useful biomarkers of dissociation and advancing our understanding of its neural mechanisms.

Childhood maltreatment type and severity predict depersonalization and derealization in treatment-seeking women with posttraumatic stress disorder.

The dissociative subtype of posttraumatic stress disorder (D-PTSD) is estimated to occur in approximately 14% of those with posttraumatic stress disorder (PTSD), and is characterized by clinically significant dissociative symptoms in addition to typical PTSD symptoms. Prior research has found childhood maltreatment contributes to dissociation and D-PTSD susceptibility, but more nuanced questions about the nature of childhood maltreatment remain unexplored. We investigated how childhood maltreatment type and severity are associated with the dissociative symptoms of D-PTSD among women with PTSD (N = 106) receiving psychiatric care at a program specializing in trauma-related disorders. Participants completed self-report surveys of psychiatric symptoms and prior trauma exposure including the PTSD Checklist for DSM-5, the Dissociative Subtype of PTSD Scale, and the Childhood Trauma Questionnaire. We used multivariate linear regression to model the association of childhood maltreatment types and dissociation. In our final model childhood emotional abuse and physical abuse significantly predicted the dissociative symptoms of D-PTSD. This suggests childhood maltreatment type and severity, in particular of emotional and physical abuse, are associated with the dissociative symptoms of D-PTSD. This work points toward potential etiological contributions to D-PTSD.

Dissociative subtype of posttraumatic stress disorder in women in partial and residential levels of psychiatric care.

The dissociative subtype of posttraumatic stress disorder (PTSD) is estimated to characterize about 12-30% of those with PTSD. Some research links this subtype with increased severity of PTSD symptoms compared to samples with "classic" PTSD. However, prevalence and severity rates reported in the literature have varied. One possible explanation for these discrepancies could be related to where the populations were sampled. Therefore, we investigated whether these differences are still observed when holding level of care constant. We collected data from 104 women at a partial and residential psychiatric hospital program focused on trauma-related disorders. Participants completed self-report questionnaires assessing trauma exposure, symptoms and provisional diagnosis of PTSD, trauma-related thoughts and beliefs, and feelings of shame. All participants reported a history of childhood and/or adulthood trauma exposure. Eighty-eight (85%) met criteria for PTSD, and of those, seventy-three (83%) met criteria for the dissociative subtype as assessed by the Dissociative Subtype of PTSD Scale. A series of independent t-tests revealed no significant differences between the "classic" and dissociative PTSD groups with respect to lifetime or childhood trauma exposure, posttraumatic cognitions, shame, or overall PTSD severity. Our results suggest that samples with classic PTSD and the dissociative subtype may not differ in some types of symptom severity when holding level of care constant. Importantly, however, we found at partial/residential level of care the majority of patients with PTSD were dissociative. Given the elevated prevalence rate in this sample, these findings support the need to assess dissociative symptoms, particularly in more acute psychiatric settings.

Autonomic responses to fear conditioning among women with PTSD and dissociation.

BACKGROUND: Individuals with posttraumatic stress disorder (PTSD) demonstrate alterations in autonomic responses to fear conditioning, such as exaggerated startle and poor fear inhibition. However, there is a paucity of research on fear conditioning among individuals with PTSD and dissociative symptoms, which represents 10-30% of those with PTSD. The current study used a fear-potentiated startle (FPS) conditioning paradigm to examine autonomic responses among women with PTSD and a range of dissociative symptoms. METHODS: Participants included 39 women with PTSD and dissociation, and 53 women with PTSD with unknown levels of dissociation. The FPS paradigm consisted of conditioned stimuli associated and not associated with an aversive unconditioned stimulus. FPS response (eyeblink startle), electrocardiogram (ECG), and skin conductance response (SCR) were collected during the FPS paradigm. RESULTS: Compared to the PTSD-unknown dissociation sample, the PTSD-dissociation sample demonstrated significantly lower FPS during the last block of conditioning. Among the PTSD-dissociation sample, higher dissociation scores were associated with decreased FPS and SCR, and higher respiratory sinus arrhythmia (derived from ECG). CONCLUSIONS: Results suggest that autonomic responses to fear conditioning differ depending on the presence and severity of dissociative symptoms. Given that treatment response may differ depending on dissociative symptoms, it is important to understand the mechanisms that underlie different subtypes of PTSD and that may affect treatment response and outcome.

Augmentation of Extinction and Inhibitory Learning in Anxiety and Trauma-Related Disorders.

Although the fear response is an adaptive response to threatening situations, a number of psychiatric disorders feature prominent fear-related symptoms caused, in part, by failures of extinction and inhibitory learning. The translational nature of fear conditioning paradigms has enabled us to develop a nuanced understanding of extinction and inhibitory learning based on the molecular substrates to systems neural circuitry and psychological mechanisms. This knowledge has facilitated the development of novel interventions that may augment extinction and inhibitory learning. These interventions include nonpharmacological techniques, such as behavioral methods to implement during psychotherapy, as well as device-based stimulation techniques that enhance or reduce activity in different regions of the brain. There is also emerging support for a number of psychopharmacological interventions that may augment extinction and inhibitory learning specifically if administered in conjunction with exposure-based psychotherapy. This growing body of research may offer promising novel techniques to address debilitating transdiagnostic fear-related symptoms.

Preliminary Evidence of a Missing Self Bias in Face Perception for Individuals with Dissociative Identity Disorder.

Failing to recognize one's mirror image can signal an abnormality in one's sense of self. In dissociative identity disorder (DID), individuals often report that their mirror image can feel unfamiliar or distorted. They also experience some of their own thoughts, emotions, and bodily sensations as if they are nonautobiographical and sometimes as if instead, they belong to someone else. To assess these experiences, we designed a novel backwards masking paradigm in which participants were covertly shown their own face, masked by a stranger's face. Participants rated feelings of familiarity associated with the strangers' faces. 21 control participants without trauma-generated dissociation rated masks, which were covertly preceded by their own face, as more familiar compared to masks preceded by a stranger's face. In contrast, across two samples, 28 individuals with DID and similar clinical presentations (DSM-IV Dissociative Disorder Not Otherwise Specified type 1) did not show increased familiarity ratings to their own masked face. However, their familiarity ratings interacted with self-reported identity state integration. Individuals with higher levels of identity state integration had response patterns similar to control participants. These data provide empirical evidence of aberrant self-referential processing in DID/DDNOS and suggest this is restored with identity state integration.

Assessing Voice Hearing in Trauma Spectrum Disorders: A Comparison of Two Measures and a Review of the Literature.

Voice hearing (VH) can occur in trauma spectrum disorders (TSD) such as posttraumatic stress disorder (PTSD) and dissociative disorders. However, previous estimates of VH among individuals with TSD vary widely. In this study, we sought to better characterize the rate and phenomenology of VH in a sample of 70 women with TSD related to childhood abuse who were receiving care in a specialized trauma program. We compared the rate of VH within our sample using two different measures: 1) the auditory hallucination (AH) item in the Structured Clinical Interview for DSM-IV-TR (SCID), and 2) the thirteen questions involving VH in the Multidimensional Inventory of Dissociation (MID), a self-report questionnaire that comprehensively assesses pathological dissociation. We found that 45.7% of our sample met threshold for SCID AH, while 91.4% met criteria for MID VH. Receiver operating characteristics (ROC) analyses showed that while SCID AH and MID VH items have greater than chance agreement, the strength of agreement is only moderate, suggesting that SCID and MID VH items measure related but not identical constructs. Thirty-two patients met criteria for both SCID AH and at least one MID VH item ("unequivocal VH"), 32 for at least one MID VH item but not SCID AH ("ambiguous VH"), and 6 met criteria for neither ("unequivocal non-VH"). Relative to the ambiguous VH group, the unequivocal VH group had higher dissociation scores for child voices, and higher mean frequencies for child voices and Schneiderian voices. Our findings suggest that VH in women with TSD related to childhood abuse is common, but that the rate of VH depends on how the question is asked. We review prior studies examining AH and/or VH in TSD, focusing on the measures used to ascertain these experiences, and conclude that our two estimates are consistent with previous studies that used comparable instruments and patient samples. Our results add to growing evidence that VH-an experience typically considered psychotic or psychotic-like-is not equivalent to having a psychotic disorder. Instruments that assess VH apart from psychotic disorders and that capture their multidimensional nature may improve identification of VH, especially among patients with non-psychotic disorders.

Conceptualization, Assessment, and Treatment of Traumatic Stress in First Responders: A Review of Critical Issues.

First responders are regularly confronted with exposure to traumatic events, including potentially life-threatening situations as well as the grave injuries and deaths of colleagues and civilians. Evidence indicates that the prevalence of posttraumatic stress disorder (PTSD) is substantially higher among first responders than the general population. This article provides information about the outpatient trauma services at McLean Hospital's LEADER (Law Enforcement, Active Duty, Emergency Responder) program to assist clinicians who encounter these first responders in their practices or who are specifically interested in working with this patient population. We begin by synthesizing the literature on the prevalence of PTSD in first responders following work-related exposure to traumatic stress, and by addressing the occupation-specific risk factors and the third-variable risk factors that may contribute to potentiated risk. We then discuss assessment strategies and treatment options used in our program, which is tailored for individuals who are dealing with mental health issues stemming from occupation-specific traumatic-stress exposure. We also address the unique challenges of treating traumatized first responders with more complex issues such as traumatic stress exposure across the lifespan and safety issues, including acute suicidality. We conclude by discussing notable gaps in the literature, including the need to investigate why and how women present with different PTSD symptoms than men and how these differences need to be taken into account in determining appropriate treatment for women.

Smaller Hippocampal Volume in Posttraumatic Stress Disorder: A Multisite ENIGMA-PGC Study: Subcortical Volumetry Results From Posttraumatic Stress Disorder Consortia.

BACKGROUND: Many studies report smaller hippocampal and amygdala volumes in posttraumatic stress disorder (PTSD), but findings have not always been consistent. Here, we present the results of a large-scale neuroimaging consortium study on PTSD conducted by the Psychiatric Genomics Consortium (PGC)-Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) PTSD Working Group. METHODS: We analyzed neuroimaging and clinical data from 1868 subjects (794 PTSD patients) contributed by 16 cohorts, representing the largest neuroimaging study of PTSD to date. We assessed the volumes of eight subcortical structures (nucleus accumbens, amygdala, caudate, hippocampus, pallidum, putamen, thalamus, and lateral ventricle). We used a standardized image-analysis and quality-control pipeline established by the ENIGMA consortium. RESULTS: In a meta-analysis of all samples, we found significantly smaller hippocampi in subjects with current PTSD compared with trauma-exposed control subjects (Cohen's d = -0.17, p = .00054), and smaller amygdalae (d = -0.11, p = .025), although the amygdala finding did not survive a significance level that was Bonferroni corrected for multiple subcortical region comparisons (p < .0063). CONCLUSIONS: Our study is not subject to the biases of meta-analyses of published data, and it represents an important milestone in an ongoing collaborative effort to examine the neurobiological underpinnings of PTSD and the brain's response to trauma.

Neuroimaging genetic approaches to Posttraumatic Stress Disorder.

Neuroimaging genetic studies that associate genetic and epigenetic variation with neural activity or structure provide an opportunity to link genes to psychiatric disorders, often before psychopathology is discernable in behavior. Here we review neuroimaging genetics studies with participants who have Posttraumatic Stress Disorder (PTSD). Results show that genes related to the physiological stress response (e.g., glucocorticoid receptor and activity, neuroendocrine release), learning and memory (e.g., plasticity), mood, and pain perception are tied to neural intermediate phenotypes associated with PTSD. These genes are associated with and sometimes predict neural structure and function in areas involved in attention, executive function, memory, decision-making, emotion regulation, salience of potential threats, and pain perception. Evidence suggests these risk polymorphisms and neural intermediate phenotypes are vulnerabilities toward developing PTSD in the aftermath of trauma, or vulnerabilities toward particular symptoms once PTSD has developed. Work distinguishing between the re-experiencing and dissociative sub-types of PTSD, and examining other PTSD symptom clusters in addition to the re-experiencing and hyperarousal symptoms, will further clarify neurobiological mechanisms and inconsistent findings. Furthermore, an exciting possibility is that genetic associations with PTSD may eventually be understood through differential intermediate phenotypes of neural circuit structure and function, possibly underlying the different symptom clusters seen within PTSD.