Hard on the heels of stress

Many people already experienced incredible stress as schoolchildren when their math teacher summoned them to the blackboard to solve an equation in front of the whole class. The test subjects in a study conducted by Stefan Röpke and his research team on post-traumatic stress disorders (PTSD) have a similar experience: in the Trier Social Stress Test, test subjects have to give a lecture in front of a jury – only, no matter what the person says, the jury displays a very dismissive attitude. No wonder that causes stress in many people. By contrast, test subjects in the control group only have to recite the lecture to themselves. Following this, both groups are shown a film that can cause short-term symptoms of PTSD even in healthy people. The film contains images of undesired, disturbing events – for instance, images of car accidents, war scenes or extreme acts of violence.

Stefan Röpke, senior physician in Department of Psychiatry and Psychotherapy of the Charité, explains: “Human beings have the ability to notice stressful events more vividly, in order to not repeat mistakes or to encounter dangerous things with extra caution”. When mentally processing such events, many people experience intrusive memories. These are memories or images of a past event that obtrude repeatedly.” Similar stimuli, sounds or smells in their environment make PTSD sufferers feel as if they’re experiencing the event all over again. This can go so far that sufferers feel “torn from their everyday lives and even avoid certain situations, due to which their lives become ever more restricted,” says Röpke. These kinds of intrusive memories are often symptoms of a post-traumatic stress disorder. In the case of soldiers who return from deployment abroad, the public is at least partly sensitized to this issue. PTSD is also increasingly the subject of public discussion in connection with severely traumatized refugees.

At the clinic, Stefan Röpke and his team are confronted daily with the problem of intrusive memories in patients with PTSD. It is problematic that little is known about the development of such disorders: “We do know about certain influencing factors relating, for instance, to earlier traumas or feelings of guilt,” he explains. There are also some successful psychotherapeutic approaches, but effective pharmacological therapies are lacking. His research group is therefore trying to ascertain what happens in the stress systems of the body at the biological level when these stress disorders are triggered. This will potentially make it possible to influence these trigger mechanisms in future, and to use the insights gained to both prevent and treat PTSD.

Stefan Röpke and his team therefore expose their test subjects to the influence of various stress factors, to understand the influence of hormones in the development of intrusive memories. 

In the experiment, the researchers observe how frequently and how vividly the test groups experienced intrusive images of the film excerpts shown to them. The results of the study show that the film excerpts caused more intrusive memories in those test subjects whose biological stress systems were activated by the foregoing stress test.