To overcome post-traumatic stress disorder, certain inhibitory mechanisms, capable of blocking the resurgence of memories, are essential, concludes new research carried out on a hundred people exposed to the Paris attacks of 2015.
Between the attacks on Charlie Hebdo and the Hyper Casher in January and those on the Bataclan, the Stade de France and several bars and restaurants in November, 2015 was a dark year for the city of Paris.
Chronicles in 20% of cases according to Inserm, post-traumatic stress disorder (PTSD) is manifested by intrusive and therefore unwanted memories of the event that caused the trauma, with associated intense emotions. This implies that inhibitory control mechanisms are essential for resilience, not only to reduce the vividness of memories, but also to mitigate the chronic effects of stress on the brain associated with intrusive thinking.", the researchers ask in the publication of Science Advances.
Better inhibition of memories in people in remission
It is among the survivors of the Paris attacks of 2015 that scientists recruited several dozen people with the "November 13 Program", the objective of which is to study the evolution of individual and collective memory after a traumatic event. After having them learn pairs of words, the researchers gave the subjects an MRI and asked them to stop themselves from thinking about the word associated with the one they would give them.
They found that patients in remission were better at inhibiting the intrusion of the forbidden word than people with chronic PTSD. Moreover, success on the test was correlated with a more positive course of the disorder. Normalization of inhibitory control processes, which regulate the resurfacing of intrusive memories in the hippocampus, not only predicted PTSD remission but also preceded a reduction in traumatic memories", the researchers conclude.
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Reducing stress and its damage, when a vicious circle becomes virtuous
Patients with chronic PTSD also showed signs of stress-induced atrophy in the hippocampus, particularly in the dentate gyrus, an area involved in memory. In people in remission, this atrophy was compensated for and stopped by the more effective inhibitory mechanisms, demonstrating a brain plasticity essential to healing PTSD.
According to the researchers, persistently reliving these traumatic memories is accompanied by oxidative stress and inflammation, causing a constant state of alertness, hyperarousal and an alteration of the fear response, which in turn exacerbate the intrusion of unwanted memories. A vicious cycle that becomes virtuous when the memory control system limits the access of consciousness to these intrusive memories and reduces the damage caused by stress on the hippocampus. These results suggest that restoring control mechanisms initiates remission, which may benefit the hippocampus and support the recovery process in a virtuous cycle.", the researchers conclude.
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