What chemistry in the brain triggers PTSD

Post-traumatic stress disorder: what happens in the brain

Up to five percent of people in Western countries will develop post-traumatic stress disorder (PTSD) in their lifetime. It usually occurs within six months after a traumatic event such as physical or sexual violence, natural disasters, wars or accidents. In everyday life, those affected are suddenly and uncontrollably flooded with memories of the terrible event and put back into the traumatic situation - one speaks of an intrusion

Salzburg psychologists have now used imaging techniques to observe what happens in the brain during a traumatic event. The researchers were able to show that only the combination of unfavorable neuronal processing of a trauma and negative life events that have already been experienced leads to symptoms of the disorder. The study was published in the journal "Biological Psychiatry".

"If we better understand why some people are more prone to intrusions after a psychological trauma, while others seem to be resilient, we could use this specifically for the prevention and treatment of post-traumatic stress disorders," says project leader Frank Wilhelm, head of the laboratory for Clinical stress and emotion research at the University of Salzburg.

Neural processing

A previously unanswered question about the risk and resilience factors for intrusions was what role neuronal processing plays during trauma. Since it is impossible to research this on real trauma, the Salzburg researchers developed an experiment (analog model) with which they could simulate a traumatic experience at a low and tolerable level and observe it in real time in the brain scanner.

Julina Rattel, first author of the study: "We showed 53 female test subjects aversive film clips with interpersonal violence and physical injuries, for example some scenes from the Oscar-winning Hollywood thriller '127 Hours'. With the fMRI, the functional magnetic resonance tomography, the activated brain areas can in high spatial resolution. This enables us to study how the brain deals with such emotional events. "

In the days that followed, the test subjects documented their intrusive and stressful memories of these film scenes using smartphone-based questionnaires.

Clear connection

"There was a clear connection between overactivation in certain brain regions - namely those who are responsible in particular for processing threats, for regulating emotions and storing memory contents - and increased intrusions. However, this was only the case with those people who - according to their questionnaire information - had previously experienced five or more stressful life events, "said Rattel. Those who reported no or only a few such life events, their brain areas were also active, but the intrusive and stressful reliving of the film scenes did not occur as a result.

It has long been known that previous negative life events, especially those experienced in childhood, increase vulnerability to post-traumatic stress disorder. "Our results show significantly that this can be explained by specific vulnerable brain networks that seem to be sensitized by repeated life events and, when reactivated, lead to symptoms of post-traumatic stress disorder," explains Rattel.

The findings of the Salzburg psychologists could help identify people at risk and develop potential starting points for preventive interventions after traumatic experiences. Rattel: "The question arises whether it is possible to reverse the findings through emotion training. If people who have already had several traumatic experiences receive emotion regulation training that specifically affects the brain networks we have identified, this should lead to a higher level of resilience real traumatic experiences. That's our turn. "

Eliminate grievances

For Wilhelm, the study once again confirms social responsibility in the prevention of mental disorders, especially in childhood. "About 50 percent of mental disorders have their roots in childhood, due to emotional, physical or sexual violence - at home or in other contexts, such as the abuse scandal in the church. But neglect due to a dysfunctional home is also a problem."

Most of these children would not develop any mental disorders as adults if they hadn't been traumatized, says Wilhelm. "Society must work to remedy these grievances. (Red, April 23, 2019)