Neurobiological Underpinnings of Trauma-related Psychopathology

The understanding and treatment of trauma-related psychopathology is a crucial challenge in the field of global mental health today. The etiology and mechanisms of two common trauma-related symptoms – intrusive re-experiencing and dissociative symptomatology – are still not well understood. The present work aims to advance the understanding of these phenomena by investigating their neurobiological underpinnings in two disorders: depersonalization/derealization disorder (DPD), in which dissociation depicts the core feature, and the dissociative subtype of posttraumatic stress disorder (PTSD-D), in which dissociative symptomatology and intrusive re-experiencing co-occur and correlate in regard to their severity. Alterations in fiber tract networks in white matter, which are crucial for communicating between brain regions, have not yet been investigated in DPD or PTSD-D. In Study I, white matter network alterations were explored in 23 patients with DPD compared to 23 matched healthy controls. Results yielded relatively lower structural connectivity in left and right temporal regions in DPD, which have previously been associated with dissociative symptomatology in DPD and in other disorders. Furthermore, a trend indicated alterations in a fronto-limbic circuit, which a neurobiological model proposes underlies dissociation in DPD as well as PTSD-D. In Study II, we tested whether fronto-limbic circuits are also altered in PTSD-D (n=23) compared to ‘classic’ PTSD patients (n=19) using the same analysis pipeline as in Study I. No respective white matter changes were detected on a network level in PTSD-D. However, subsequent exploratory analyses revealed alterations in two subcortical networks comprising a limbic-thalamic circuit and low-level motor regions, respectively. The limbic-thalamic network is crucial for declarative and spatial mnemonic processes, which according to dual memory models play a crucial role for the development of intrusive memories. We tested the respective memory model in Study III and confirmed for the first time empirically, that spatial-contextual (allocentric) memory ability is negatively associated with severity of intrusive memories in 33 patients with PTSD. The findings of the present work indicate that (1) dissociation in DPD is underpinned by different alterations in structural connectivity than in PTSD-D and (2) dissociative and intrusive memories are associated with aberrations in similar sub-cortical circuits, supporting the notion that in PTSD-D, a lower state of consciousness exacerbates de-contextualization of the traumatic content, resulting in heightened intrusive symptomatology. Clinical implications of our findings are discussed

Intrusive Images in Psychological Disorders: Characteristics, Neural Mechanisms, and Treatment Implications

Involuntary images and visual memories are prominent in many types of psychopathology. Patients with posttraumatic stress disorder, other anxiety disorders, depression, eating disorders, and psychosis frequently report repeated visual intrusions corresponding to a small number of real or imaginary events, usually extremely vivid, detailed, and with highly distressing content. Both memory and imagery appear to rely on common networks involving medial prefrontal regions, posterior regions in the medial and lateral parietal cortices, the lateral temporal cortex, and the medial temporal lobe. Evidence from cognitive psychology and neuroscience implies distinct neural bases to abstract, flexible, contextualized representations (C-reps) and to inflexible, sensory-bound representations (S-reps). We revise our previous dual representation theory of posttraumatic stress disorder to place it within a neural systems model of healthy memory and imagery. The revised model is used to explain how the different types of distressing visual intrusions associated with clinical disorders arise, in terms of the need for correct interaction between the neural systems supporting S-reps and C-reps via visuospatial working memory. Finally, we discuss the treatment implications of the new model and relate it to existing forms of psychological therapy

Neurobiological Underpinnings of Trauma-related Psychopathology

The understanding and treatment of trauma-related psychopathology is a crucial challenge in the field of global mental health today. The etiology and mechanisms of two common trauma-related symptoms – intrusive re-experiencing and dissociative symptomatology – are still not well understood. The present work aims to advance the understanding of these phenomena by investigating their neurobiological underpinnings in two disorders: depersonalization/derealization disorder (DPD), in which dissociation depicts the core feature, and the dissociative subtype of posttraumatic stress disorder (PTSD-D), in which dissociative symptomatology and intrusive re-experiencing co-occur and correlate in regard to their severity. Alterations in fiber tract networks in white matter, which are crucial for communicating between brain regions, have not yet been investigated in DPD or PTSD-D. In Study I, white matter network alterations were explored in 23 patients with DPD compared to 23 matched healthy controls. Results yielded relatively lower structural connectivity in left and right temporal regions in DPD, which have previously been associated with dissociative symptomatology in DPD and in other disorders. Furthermore, a trend indicated alterations in a fronto-limbic circuit, which a neurobiological model proposes underlies dissociation in DPD as well as PTSD-D. In Study II, we tested whether fronto-limbic circuits are also altered in PTSD-D (n=23) compared to ‘classic’ PTSD patients (n=19) using the same analysis pipeline as in Study I. No respective white matter changes were detected on a network level in PTSD-D. However, subsequent exploratory analyses revealed alterations in two subcortical networks comprising a limbic-thalamic circuit and low-level motor regions, respectively. The limbic-thalamic network is crucial for declarative and spatial mnemonic processes, which according to dual memory models play a crucial role for the development of intrusive memories. We tested the respective memory model in Study III and confirmed for the first time empirically, that spatial-contextual (allocentric) memory ability is negatively associated with severity of intrusive memories in 33 patients with PTSD. The findings of the present work indicate that (1) dissociation in DPD is underpinned by different alterations in structural connectivity than in PTSD-D and (2) dissociative and intrusive memories are associated with aberrations in similar sub-cortical circuits, supporting the notion that in PTSD-D, a lower state of consciousness exacerbates de-contextualization of the traumatic content, resulting in heightened intrusive symptomatology. Clinical implications of our findings are discussed

Intrusive memories of trauma: A target for research bridging cognitive science and its clinical application.

Intrusive memories of a traumatic event can be distressing and disruptive, and comprise a core clinical feature of post-traumatic stress disorder (PTSD). Intrusive memories involve mental imagery-based impressions that intrude into mind involuntarily, and are emotional. Here we consider how recent advances in cognitive science have fueled our understanding of the development and possible treatment of intrusive memories of trauma. We conducted a systematic literature search in PubMed, selecting articles published from 2008 to 2018 that used the terms "trauma" AND ("intrusive memories" OR "involuntary memories") in their abstract or title. First, we discuss studies that investigated internal (neural, hormonal, psychophysiological, and cognitive) processes that contribute to intrusive memory development. Second, we discuss studies that targeted these processes using behavioural/pharmacological interventions to reduce intrusive memories. Third, we consider possible clinical implications of this work and highlight some emerging research avenues for treatment and prevention, supplemented by new data to examine some unanswered questions. In conclusion, we raise the possibility that intrusive memories comprise an alternative, possibly more focused, target in translational research endeavours, rather than only targeting overall symptoms of disorders such as PTSD. If so, relatively simple approaches could help to address the need for easy-to-deliver, widely-scalable trauma interventions

The Memory and Identity Theory of ICD-11Complex Posttraumatic Stress Disorder

The 11th version of the International Classification of Diseases (ICD-11) includes complex posttraumatic stress disorder (CPTSD) as a separate diagnostic entity alongside posttraumatic stress disorder (PTSD). ICD-11 CPTSD is defined by six sets of symptoms, three that are shared with PTSD (reexperiencing in the here and now, avoidance, and sense of current threat) and three (affective dysregulation, negative self-concept, and disturbances in relationships) representing pervasive “disturbances in self-organization” (DSO). There is considerable evidence supporting the construct validity of ICD-11 CPTSD, but no theoretical account of its development has thus far been presented. A theory is needed to explain several phenomena that are especially relevant to ICD-11 CPTSD such as the role played by prolonged and repeated trauma exposure, the functional independence between PTSD and DSO symptoms, and diagnostic heterogeneity following trauma exposure. The memory and identity theory of ICD-11 CPTSD states that single and multiple trauma exposure occur in a context of individual vulnerability which interact to give rise to intrusive, sensation-based traumatic memories and negative identities which, together, produce the PTSD and DSO symptoms that define ICD-11 CPTSD. The model emphasizes that the two major and related causal processes of intrusive memories and negative identities exist on a continuum from pre-reflective experience to full self-awareness. Theoretically derived implications for the assessment and treatment of ICD-11 CPTSD are discussed, as well as areas for future research and model testing

Peritraumatic Reactions and Intrusive Memories among Disaster Survivors: A Mixed Methods Investigation

Intrusive memories represent a hallmark symptom of post-traumatic stress disorder (PTSD). Cognitive theories of PTSD hypothesize that intrusive memories result from disruptions in information processing during traumatic memory encoding. The affective, cognitive, and behavioural reactions taking place during trauma have been termed peritraumatic reactions. These include reactions such as peritraumatic dissociation and tonic immobility. Experimental evidence has supported the theoretical claims concerning the role of peritraumatic reactions in the development of intrusive memories. This literature, however, presents a number of limitations. First, it relies on a conceptualisation of peritraumatic reactions based largely on quantitative measures with a large degree of conceptual overlap. Secondly, the identification of peritraumatic reactions has relied on clinical expertise, theory, and animal models, rather than on systematic investigations of survivors’ lived experience. Finally, studies on peritraumatic reactions and intrusive memories, have generally assessed peritraumatic reactions for the entire trauma rather than for the specific moments experienced as intrusive memories. This thesis set out to address these limitations. Firstly, I investigated the factorial structure of the six most widely used peritraumatic measures. This led to the identification of a psychometrically validated model comprising five distinct peritraumatic reactions. Secondly, I explored using a largely inductive analytical framework the lived experienced of peritraumatic reactions spontaneously reported in interviews. Finally, building on these findings, I confirmed the theory-informed claims that the specific moments of a trauma experienced as intrusive memories would be characterised by higher levels of peritraumatic reactions compared to moments from the same trauma that did not intrude. All research was conducted among earthquake survivors. The current findings hold various implications for the conceptualisation of peritraumatic reactions and intrusive memories. Additionally, they have a number of practical implications for the prevention and management of intrusive memories as well as for the wellbeing of disaster survivors more generally

The memory and identity theory of ICD-11 complex posttraumatic stress disorder

The 11th version of the International Classification of Diseases (ICD-11) includes complex posttraumatic stress disorder (CPTSD) as a separate diagnostic entity alongside posttraumatic stress disorder (PTSD). ICD-11 CPTSD is defined by six sets of symptoms, three that are shared with PTSD (reexperiencing in the here and now, avoidance, and sense of current threat) and three (affective dysregulation, negative self-concept, and disturbances in relationships) representing pervasive "disturbances in self-organization" (DSO). There is considerable evidence supporting the construct validity of ICD-11 CPTSD, but no theoretical account of its development has thus far been presented. A theory is needed to explain several phenomena that are especially relevant to ICD-11 CPTSD such as the role played by prolonged and repeated trauma exposure, the functional independence between PTSD and DSO symptoms, and diagnostic heterogeneity following trauma exposure. The memory and identity theory of ICD-11 CPTSD states that single and multiple trauma exposure occur in a context of individual vulnerability which interact to give rise to intrusive, sensation-based traumatic memories and negative identities which, together, produce the PTSD and DSO symptoms that define ICD-11 CPTSD. The model emphasizes that the two major and related causal processes of intrusive memories and negative identities exist on a continuum from prereflective experience to full self-awareness. Theoretically derived implications for the assessment and treatment of ICD-11 CPTSD are discussed, as well as areas for future research and model testing. (PsycInfo Database Record (c) 2023 APA, all rights reserved)

Memory reconsolidation in trauma-like memory

Individuals might meet difficulties in updating and integrating traumatic memories with existing autobiographical memories, which could lead to posttraumatic stress disorder. Eye Movement Desensitisation and Reprocessing (EMDR) therapy putatively facilitates adaptive memory updating and integration. While eye movement is critical to the therapeutic benefit of EMDR, their mechanism of action remains unclear. We applied video trauma memory with counterconditioning to test the effect of eye movement in EMDR directly. We also explored the importance of internet-based interventions and culture differences in updating trauma-like memories. In experiment 1, we recruited 69 undergraduates from the University of Birmingham. Participants were exposed to distressing film clips and counterconditioning took place a day later. Subjective distress was recorded daily for one week, and declarative memory for the trauma video was also tested on the final day. In experiment 2, we recruited 35 healthy participants from the Southwest University in China and 24 healthy participants from the University of Birmingham; 26 participants completed their experiments in person, and 33 participants completed their experiments online. The experimental procedures were the same as the ones in experiment 1. The results in experiment 1 indicated that eye movement combined with counterconditioning had the lowest IES-R scores among all the groups, but these results were not repeated in declarative memory tasks. In experiment 2, we replicated the effect (eye movement + war + humour) in different cultures and types. However, we only compared the difference between fully memory reconsolidation condition (eye movement + counterconditioning) and control group. Therefore, we were unable to conclude that eye movement can enhance memory reconsolidation, but counterconditioning might play an important role in memory reconsolidation which is a universal phenomenon