Neurobiological and genetic correlates of the dissociative subtype of posttraumatic stress disorder

Dissociative Subtype of Posttraumatic Stress Disorder and its Correlates Among Treatment-Seeking Refugees

The dissociative subtype of posttraumatic stress disorder (PTSD-DS) denotes a severe type of PTSD associated with complex trauma exposure and psychiatric comorbidity. Refugees may be at heightened risk of developing PTSD-DS, but research is lacking. This cross-sectional study aimed to examine PTSD-DS and its demographic, trauma-related, and clinical correlates among a convenience sample of refugee patients over 18 years old who were diagnosed with PTSD according to DSM-5. PTSD-DS (Clinician-Administered PTSD Scale for DSM-5), trauma exposure (Life Events Checklist for DSM-5) and general psychopathology (Brief Symptom Inventory) were assessed at intake. T-tests, chi-square tests, and logistical regression analysis were conducted. The final sample consisted of 552 participants (177 (32.1%) women; 375 (67.9%) men; average age 40.0 years (SD = 11.2)) who originated from 63 countries. Of those, 158 (28.6%) met criteria for PTSD-DS. Participants with PTSD-DS scored significantly higher on PTSD symptom severity (t(550)=-5.270, p < .001), number of traumatic event types (t(456)=-3.499, p < .001), and exposure to sexual assault (χ(1) = 6.471, p = .01) than those without PTSD-DS. The odds of having PTSD-DS increased by 14.1% with exposure to each additional traumatic event type (OR = 1.141, CI 0.033-1.260). In conclusion, around 29% of adult treatment-seeking refugees with PTSD met the criteria for PTSD-DS. Those exposed to multiple traumatic event types including sexual assault, regardless of sex, were especially at risk. Having PTSD-DS was associated with more severe PTSD. Prioritizing trauma-focused treatment for those with PTSD-DS is recommended.

Enhancing Agency in Posttraumatic Stress Disorder Therapies Through Sensorimotor Technologies

Posttraumatic stress disorder (PTSD) is a significant public health concern, with only a third of patients recovering within a year of treatment. While PTSD often disrupts the sense of body ownership and sense of agency (SA), attention to the SA in trauma has been lacking. This perspective paper explores the loss of the SA in PTSD and its relevance in the development of symptoms. Trauma is viewed as a breakdown of the SA, related to a freeze response, with peritraumatic dissociation increasing the risk of PTSD. Drawing from embodied cognition, we propose an enactive perspective of PTSD, suggesting therapies that restore the SA through direct engagement with the body and environment. We discuss the potential of agency-based therapies and innovative technologies such as gesture sonification, which translates body movements into sounds to enhance the SA. Gesture sonification offers a screen-free, noninvasive approach that could complement existing trauma-focused therapies. We emphasize the need for interdisciplinary collaboration and clinical research to further explore these approaches in preventing and treating PTSD.

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.

Longitudinal study of traumatic-stress related cellular and cognitive aging

Traumatic stress is associated with both accelerated epigenetic age and increased risk for dementia. Accelerated epigenetic age might link symptoms of traumatic stress to dementia-associated biomarkers, such as amyloid-beta (Aβ) proteins, neurofilament light (NFL), and inflammatory molecules. We tested this hypothesis using longitudinal data obtained from 214 trauma-exposed military veterans (85 % male, mean age at baseline: 53 years, 75 % White) who were assessed twice over the course of an average of 5.6 years. Cross-lagged panel mediation models evaluated measures of lifetime posttraumatic stress disorder and internalizing and externalizing comorbidity (assessed at Time 1; T1) in association with T1 epigenetic age (per the GrimAge algorithm) and T1 plasma markers of neuropathology along with bidirectional temporal paths between T1 and T2 epigenetic age and the plasma markers. Results revealed that a measure of externalizing comorbidity was associated with accelerated epigenetic age (β = 0.30, p <.01), which in turn, was associated with subsequent increases in Aβ-40 (β = 0.20, p <.001), Aβ-42 (β = 0.18, p <.001), and interleukin-6 (β = 0.18, p <.01). T1 advanced epigenetic age and the T1 neuropathology biomarkers NFL and glial fibrillary acidic protein predicted worse performance on T2 neurocognitive tasks assessing working memory, executive/attentional control, and/or verbal memory (ps = 0.03 to 0.009). Results suggest that advanced GrimAge is predictive of subsequent increases in neuropathology and inflammatory biomarkers as well as worse cognitive function, highlighting the clinical significance of this biomarker with respect to cognitive aging and brain health over time. The finding that advanced GrimAge mediated the association between psychiatric comorbidity and future neuropathology is important for understanding potential pathways to neurodegeneration and early identification of those at greatest risk.

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.