Differences in predictive factors for post-traumatic stress disorder encompassing partial PTSD and full PTSD: a cross-sectional study among individuals exposed to the November 13, 2015 Paris attacks

Background

When faced with a surge of physically injured individuals, especially following a traumatic event like an attack, frontline practitioners prioritize early triage. Detecting potential psychological injuries soon after such events remains challenging. Some individuals might develop post-traumatic stress disorder (PTSD) according to DSM-V criteria. Others may exhibit PTSD symptoms without meeting full diagnostic criteria, termed partial or sub-syndromal PTSD, a less-explored area in literature. This study aims to identify predictive factors for both full and partial PTSD.

Method

In a cohort of victims of the 2015 Paris attacks, multinomial logistic regressions explored predictive factors for partial or full PTSD status 8 to 18 months post-attacks. Analyses considered pre, peri, and posttraumatic factors chosen from literature review and univariate analysis within each group.

Results

Within the cohort, 50 individuals showed no signs of PTSD, 35 experienced partial PTSD, and 30 presented with full PTSD. After logistic regression, risk factors associated with full PTSD included a history of trauma (OR = 1.30, CI [1.02-1.66], p < 0.05), the intensity of peri-traumatic physical reactions (OR = 1.22, CI [1.09-1.36], p < 0.001), the difficulties in suppressing intrusive thoughts (OR = 1.11, CI [1.02-1.21], p < 0.013). Only the intensity of peri-traumatic physical reactions emerged as a risk factor for partial PTSD (OR = 1.13, [CI 1.02-1.24], p < 0.001).

Discussion

This study revealed that a history of trauma, the intensity of peri-traumatic physical reactions (e.g., tachycardia, trembling, flushes, numbness.), and the difficulties in suppressing intrusive thoughts constitute risk factors for the development of full PTSD. Moreover, the study identified that only the intensity of peri-traumatic physical reactions emerged as a risk factor for partial PTSD. These findings seem to underscore the significance of peri-traumatic experiences in influencing the development of post-traumatic stress symptoms.

Conclusion

This study emphasizes the significance of examining peri-traumatic reactions in PTSD development, suggesting its potential as a straightforward screening tool for post-traumatic stress disorder. It also underscores the influence of prior traumatic experiences, before de novo traumatization, in shaping vulnerability to PTSD and illuminates the crucial role of compromised control of intrusive thoughts that could perpetuate PTSD.

[The social traces of the trauma of the 13 November 2015 terrorist attacks: Five years and seven months after]

The monitoring of how public opinion memorizes the terrorist attacks from 13th November 2015, and moreover the terrorist attacks since the early 2000s, provides new material for understanding the evolution over time and the mechanisms of the construction of collective memory. Data collected to date show that these attacks had a greater impact on the population than other tragic events that have occurred in recent history in France, or even a greater impact than other and much more recent attacks. In the long term, the precise memory of the factual aspects and the memories of the personal circumstances in which people learned about the events begin to vanish. While imprecision is gaining ground, collective memory now crystallizes on very significant and overdetermined markers such as emblematic places or locations such as the "Bataclan". As a matter of fact, this imprecision of memory goes hand-in-hand with a much stronger symbolic and emotional investment of the event as a whole and leads to an overestimation of the number of terrorists or victims. The special place given to the terrorist attacks of 13th November in the collective memory is due to the unprecedented number of victims, the fact that the attacks took place in the heart of the capital city, the reaction of the public authorities who declared a long lasting state of emergency, the discursive framing of the war on terrorism in all major media, and the feeling that the Islamist threat can kill indiscriminately without targeting specific categories of the population. The study also reveals the influence of value systems (political opinions, views of the republican model) and social characteristics of individuals on the way people memorize such experiences. It is part of a fundamentally multidisciplinary research around "Memory and trauma" that includes neuroscience, biological and clinical investigations.

[The Programme 13-Novembre between individual memory and collective memory]

The purpose of this article is to present the evolution of scientific work on human memory from the end of the 19th century. The work of experimental psychology and neuropsychology first dominated the scientific scene. Research in the humanities and social sciences was established in the interwar period, but without any real interaction with psychology and neurosciences. We recall the most emblematic historical works of two distinct visions of memory: those of the experimental psychologist Hermann Ebbinghaus who measured memory, on himself, from lists of meaningless syllables, and those of the sociologist Maurice Halbwachs for whom any act of memory is a social act. This disciplinary closure persisted until the end of the 20th century. A real social shift has taken place since the 2000s, with a desire to studying and understanding the interactions between individual and collective memories. In this article, the authors argue for the emergence of "sciences of memory" based on dialectic and transdisciplinarity. They draw on the Programme 13-Novembre that is emblematic of this evolution. The Programme 13-Novembre has seized upon a diversity of research tools on memory by applying them to a traumatic event in French society: the attacks of 13 November 2015 in Paris and its immediate suburbs. Its genesis, its overall architecture and several of its components are presented here, as well as a few results already published. In addition to its theoretical scope, this work has many possible applications, particularly in the understanding and management of various pathologies, post-traumatic stress disorder being the most demonstrative in this respect.

[Memory and traumatism: From biology to humanities]

This article is a brief Introduction to a series of articles issued from the Journée Claude Bernard, organized at the Académie Nationale de Médecine. This session had for thematic "Memory and traumatism" and was composed of presentations coming from different disciplines including biological sciences and humanities. Several publications come from the Programme 13-Novembre, devoted to a traumatic event in French society - the attacks of 13 November 2015 in Paris and its immediate suburbs - and its consequences on the construction of individual and collective memories of this tragic event.

[Memories of the 13-November 2015 terrorist attacks: what discourse analysis can teach us]

The Programme 13-Novembre aims to analyze the individual and collective memory of the terrorist attacks of November 13, 2015. At its heart is the Étude 1000, which is to gather the same 1000 people in audiovisual interviews four times in 10 years. Having the transcripts at our disposal, we choose here to show the importance of discourse analysis by recalling its theoretical foundations, to present one of the tools allowing this statistical analysis, the Correspondence Factor Analysis, and to use it to analyze the sub-corpus of interviews conducted at a distance from the Paris events, with 76 inhabitants of the Metz region. Crossing these volunteers with the words they use, we see that two variables clearly stand out that oppose the vocabularies, the gender variable and the age variable.

Peritraumatic physical symptoms and the clinical trajectory of PTSD after a terrorist attack: a network model approach

Introduction: Following a mass casualty event, such as the Paris terrorist attacks of 13 November 2015, first responders need to identify individuals at risk of PTSD. Physical peritraumatic symptoms involving the autonomic nervous system may be useful in this task.Objective: We sought to determine the trajectory of physical response intensity in individuals exposed to the Paris terrorist attacks using repeated measures, and to examine its associations with PTSD. Using network modelling, we examined whether peritraumatic physical symptom associations differed by PTSD status.Methods: Physical reactions were assessed using the Subjective Physical Reactions Scale at three time points: peritraumatic by retrospective recall, then current at one year (8-18 months) and three years (30-42 months) after the attacks. Interaction networks between peritraumatic physical reactions were compared according to PTSD status.Results: On the one hand, the reported intensity of physical reactions was significantly higher in the PTSD group at all time points. On the other hand, using the dynamic approach, more robust positive interactions between peritraumatic physical reactions were found in the PTSD group one and three years after the attacks. Negative interactions were found in the no-PTSD group at one year. Peritraumatic physical numbness was found to be the most central network symptom in the PTSD group, whereas it was least central in the no-PTSD group.Discussion: Network analysis of the interaction between peritraumatic physical subjective responses, particularly physical numbness, may provide insight into the clinical course of PTSD. Our knowledge of the brain regions involved in dissociation supports the hypothesis that the periaqueductal grey may contribute to the process leading to physical numbing.Conclusions: Our findings highlight the role of peritraumatic somatic symptoms in the course of PTSD. Peritraumatic physical numbness appears to be a key marker of PTSD and its identification may help to improve early triage.

Multi-Data Integration Towards a Global Understanding of the Neurological Impact of Human Brain Severe Acute Respiratory Syndrome Coronavirus 2 Infection

As the COVID-19 pandemic continues to unfold, numerous neurological symptoms emerge. The literature reports more and more manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) related to headache, dizziness, impaired consciousness, cognitive impairment, and motor disorders. Moreover, the infection of SARS-CoV-2 may have a durable neurological impact. ACE2/TMPRSS2 is the main entry point into cells for some strains of coronaviruses (CoVs), including SARS-CoV-2, which uses it to target the central nervous system (CNS). The aim of this study was to characterize the scope of the potential complex impact of a SARS-CoV-2 infection in the brain. It concerns different scales: the topographic, cognitive, sensorimotor, and genetic one. We investigated which cognitive and sensorimotor functions are associated with the brain regions where ACE2/TMPRSS2 is overexpressed, hypothesising that they might be particularly affected by the infection. Furthermore, overexpressed genes in these regions are likely to be impacted by COVID-19. This general understanding is crucial to establish the potential neurological manifestations of the infection. Data on mRNA expression levels of genes were provided by the Allen Institute for Brain Science (AIBS), and the localisation of brain functions by the LinkRbrain platform. The latter was also used to analyze the spatial overlap between ACE2/TMPRSS2 overexpression, and either function-specific brain activations or regional overexpression of other genes. The characterisation of these overexpressed genes was based on the GeneCards platform and the gene GSE164332 from the Gene Expression Omnibus database. We analysed the cognitive and sensorimotor functions whose role might be impaired, of which 88 have been categorised into seven groups: memory and recollection, motor function, pain, lucidity, emotion, sensory, and reward. Furthermore, we categorised the genes showing a significant increase in concentration of their mRNAs in the same regions where ACE2/TMPRSS2 mRNA levels are the highest. Eleven groups emerged from a bibliographical research: neurodegenerative disease, immunity, inflammation, olfactory receptor, cancer/apoptosis, executive function, senses, ischemia, motor function, myelination, and dependence. The results of this exploration could be in relation to the neurological symptoms of COVID-19. Furthermore, some genes from peripheral blood are already considered as biomarker of COVID-19. This method could generate new hypotheses to explore the neurological manifestations of COVID-19.

Altered predictive control during memory suppression in PTSD

Aberrant predictions of future threat lead to maladaptive avoidance in individuals with post-traumatic stress disorder (PTSD). How this disruption in prediction influences the control of memory states orchestrated by the dorsolateral prefrontal cortex is unknown. We combined computational modeling and brain connectivity analyses to reveal how individuals exposed and nonexposed to the 2015 Paris terrorist attacks formed and controlled beliefs about future intrusive re-experiencing implemented in the laboratory during a memory suppression task. Exposed individuals with PTSD used beliefs excessively to control hippocampal activity during the task. When this predictive control failed, the prediction-error associated with unwanted intrusions was poorly downregulated by reactive mechanisms. This imbalance was linked to higher severity of avoidance symptoms, but not to general disturbances such as anxiety or negative affect. Conversely, trauma-exposed participants without PTSD and nonexposed individuals were able to optimally balance predictive and reactive control during the memory suppression task. These findings highlight a potential pathological mechanism occurring in individuals with PTSD rooted in the relationship between the brain’s predictive and control mechanisms.

It remains unclear how predictions of future threat affect memory recall, specifically in the case of post-traumatic stress disorder (PTSD). Here, the authors combined computational modeling and brain connectivity analyses to show that individuals with PTSD have exaggerated predictive control and reduced reactive control in a memory suppression task.

Avoidance behaviour generalizes to eye processing in posttraumatic stress disorder

BACKGROUND

Avoidance describes any action designed to prevent an uncomfortable situation or emotion from occurring. Although it is a common reaction to trauma, avoidance becomes problematic when it is the primary coping strategy, and plays a major role in the development and maintenance of posttraumatic stress disorder (PTSD). Avoidance in PTSD may generalize to non-harmful environmental cues that are perceived to be unsafe.

OBJECTIVE

We tested whether avoidance extends to social cues (i.e. emotional gazes) that are unrelated to trauma.

METHOD

A total of 159 participants (103 who had been exposed to the 2015 Paris terrorist attacks and 56 who had not) performed a gaze-cueing task featuring sad, happy and neutral faces. Attention to the eye area was recorded using an eyetracker. Of the exposed participants, 52 had been diagnosed with PTSD (PTSD+) and 51 had not developed PTSD (PTSD-). As a result of the preprocessing stages, 52 PTSD+ (29 women), 50 PTSD- (20 women) and 53 nonexposed (31 women) participants were included in the final analyses.

RESULTS

PTSD+ participants looked at sad eyes for significantly less time than PTSD- and nonexposed individuals. This effect was negatively correlated with the intensity of avoidance symptoms. No difference was found for neutral and happy faces.

CONCLUSIONS

These findings suggest that maladaptive avoidance in PTSD extends to social processing, in terms of eye contact and others' emotions that are unrelated to trauma. New therapeutic directions could include targeting sociocognitive deficits. Our findings open up new and indirect avenues for overcoming maladaptive avoidance behaviours by remediating eye processing.Trial registration: ClinicalTrials.gov identifier: NCT02810197.

HIGHLIGHTS

Avoidance is a key symptom of posttraumatic stress disorder (PTSD).Avoidance is often viewed as limited to reminders linked to the trauma.Results show that attention to the eyes of sad faces is also affected by PTSD. This effect is correlated with avoidance symptoms in PTSD.

Changes over 10 years in the retelling of the flashbulb memories of the attack of 11 September 2001

A flashbulb memory is a highly detailed and vivid autobiographical memory for the circumstances in which one first learned of a surprising, consequential and emotionally arousing event. How retelling of different features of a flashbulb memory changes over time is not totally understood. Moreover, little is known about how the emotional feeling experienced by individuals when they learned about the event modulates these changes. In this study, we explored changes over time in American individuals' retelling of their flashbulb memories of the terrorist attack of 11 September 2001. We conducted textual analysis of 824 testimonies collected from the same 206 individuals 1 week, 11, 25 and again 119 months after the attack. Results showed individuals were more likely to report temporal and emotional details in their retelling early after the event and spatial details in their long-term retelling. In addition, the intensity of emotions felt upon hearing the news about the attack influenced how individuals reported their flashbulb memories over time. Overall, this study provides further support for theories suggesting different rates of forgetting for different canonical features of emotional arousal events.

Variations in response to trauma and hippocampal subfield changes

Models of posttraumatic stress disorder (PTSD) suggest that the hippocampus is key to the persistence of traumatic memory. Yet very little is known about the precise changes that take place in this structure, nor their relation with PTSD symptoms. Previous studies have mostly used magnetic resonance imaging (MRI) at low resolutions, making it impossible to identify sensitive anatomical landmarks, or compared groups often unequally matched in terms of traumatic exposure. The present cross-sectional study included 92 individuals who had all been exposed to the terrorist attacks in Paris on November 13, 2015 (53 of whom subsequently developed PTSD) and 56 individuals who had not been exposed. Hippocampal subfield volumes were estimated using cross-validated automatic segmentation of high-resolution MRI images. Results revealed changes in CA1 and CA2-3/dentate gyrus (DG) volumes in individuals with PTSD, but not in resilient (i.e., exposed but without PTSD) individuals, after controlling for potential nuisance variables such as previous traumatic exposure and substance abuse. In line with current models of hippocampal subfield functions, CA1 changes were linked to the uncontrollable re-experiencing of intrusive memories, while CA2-3/DG changes, potentially exacerbated by comorbid depression, fostered the overgeneralization of fear linked to avoidance and hypervigilance behaviors. Additional analyses revealed that CA1 integrity was linked to optimum functioning of the memory control network in resilient individuals. These findings shed new light on potential pathophysiological mechanisms in the hippocampus subtending the development of PTSD and the failure to recover from trauma.

Long-term modulation of cardiac activity induced by inhibitory control over emotional memories

Efforts to exclude past experiences from conscious awareness can lead to forgetting. Memory suppression is central to affective disorders, but we still do not really know whether emotions, including their physiological causes, are also impacted by this process in normal functioning individuals. In two studies, we measured the after-effects of suppressing negative memories on cardiac response in healthy participants. Results of Study 1 revealed that efficient control of memories was associated with long-term inhibition of the cardiac deceleration that is normally induced by disgusting stimuli. Attempts to suppress sad memories, by contrast, aggravated the cardiac response, an effect that was closely related to the inability to forget this specific material. In Study 2, electroencephalography revealed a reduction in power in the theta (3-8 Hz), alpha (8-12 Hz) and low-beta (13-20 Hz) bands during the suppression of unwanted memories, compared with their voluntary recall. Interestingly, however, the reduction of power in the theta frequency band during memory control was related to a subsequent inhibition of the cardiac response. These results provide a neurophysiological basis for the influence of memory control mechanisms on the cardiac system, opening up new avenues and questions for treating intrusive memories using motivated forgetting.

Eye-tracking and learning experience: gaze trajectories to better understand the behavior of memorial visitors

Eye-tracking technology is increasingly introduced in museums to assess their role in learning and knowledge transfer. However, their use provide limited quantitative and/or qualitative measures such as viewing time and/or gaze trajectory on an isolated object or image (Region of Interest "ROI").The aim of this work is to evaluate the potential of the mobile eye-tracking to quantify the students’ experience and behaviors through their visit of the "Genocide and mass violence" area of the Caen memorial. In this study, we collected eye-tracking data from 17 students during their visit to the memorial. In addition, all visitors filled out a questionnaire before the visit, and a focus group was conducted before and after the visit. The first results of this study allowed us to analyze the viewing time spent by each visitor in front of 19-selected ROIs, and some of their specific sub-parts. The other important result was the reconstruction of the gaze trajectory through these ROIs. Our global trajectory approach allowed to complete the information obtained from an isolated ROI, and to identify some behaviors such as avoidance. Clustering analysis revealed some typical trajectories performed by specific sub-groups. The eye-tracking results were consolidated by the participants' answers during the focus group.

Resilience after trauma: The role of memory suppression

In the aftermath of trauma, little is known about why the unwanted and unbidden recollection of traumatic memories persists in some individuals but not others. We implemented neutral and inoffensive intrusive memories in the laboratory in a group of 102 individuals exposed to the 2015 Paris terrorist attacks and 73 nonexposed individuals, who were not in Paris during the attacks. While reexperiencing these intrusive memories, nonexposed individuals and exposed individuals without posttraumatic stress disorder (PTSD) could adaptively suppress memory activity, but exposed individuals with PTSD could not. These findings suggest that the capacity to suppress memory is central to positive posttraumatic adaptation. A generalized disruption of the memory control system could explain the maladaptive and unsuccessful suppression attempts often seen in PTSD, and this disruption should be targeted by specific treatments.

[Neuroscience and collective memory: memory schemas linking brain, societies and cultures]

During the last two decades, the effect of intersubjective relationships on cognition has been an emerging topic in cognitive neurosciences leading through a so-called "social turn" to the formation of new domains integrating society and cultures to this research area. Such inquiry has been recently extended to collective memory studies. Collective memory refers to shared representations that are constitutive of the identity of a group and distributed among all its members connected by a common history. After briefly describing those evolutions in the study of human brain and behaviors, we review recent researches that have brought together cognitive psychology, neuroscience and social sciences into collective memory studies. Using the reemerging concept of memory schema, we propose a theoretical framework allowing to account for collective memories formation with a specific focus on the encoding process of historical events. We suggest that (1) if the concept of schema has been mainly used to describe rather passive framework of knowledge, such structure may also be implied in more active fashions in the understanding of significant collective events. And, (2) if some schema researches have restricted themselves to the individual level of inquiry, we describe a strong coherence between memory and cultural frameworks. Integrating the neural basis and properties of memory schema to collective memory studies may pave the way toward a better understanding of the reciprocal interaction between individual memories and cultural resources such as media or education.