Professor Anke Ehlers: PTSD is a very disabling problem. It affects people who have been exposed to horrific events such as an assault, disaster, or severe accident. Symptoms that are very interesting from a psychological point of view are the flashback memories: people have such vivid memories of the trauma that it's as though they're back in the event and seeing and feeling things as if they're happening in the here and now.
An example would be someone who has PTSD as a result of being stabbed with a knife. They may have a flashback of the moment where the assailant is standing in front of them with the knife, and they relive the fear as if they really were in danger of dying at that moment. That's obviously very distressing but also psychologically very interesting, because it raises the question of why at that moment the patients don't realise that they are actually in a safe situation - their memory is playing a trick on them.
Most people who develop PTSD in response to a traumatic event tend to do so for a limited period of time. But in some patients the disorder persists for a long time. Why is it that the disorder is persistent in some patients but not so in others?
Most people are very resilient and get over traumatic events without professional help. For those that don't get better on their own, we identified three factors where we see differences. One is the nature of the memories: their trauma memories get stored in a way that makes them easily triggered by many things in the environment.
The second factor is the personal meaning people take away from the trauma. People with PTSD take away extremely negative meanings, usually about what the trauma means about themselves or the world, and this creates a sense that the threat from the trauma is still ongoing. For instance, if they take a trauma as meaning that they are a bad person, then the trauma remains very threatening for them in the present.
The third factor that prevents people from getting better is what they do to cope with the distressing memories and meanings. Examples are pushing the memories out of their mind and taking unnecessary precautions to stay safe. Rumination is also common: that's the tendency to dwell on the trauma or particular aspects of it, especially on questions that don't have an answer, like "why did it happen to me?". These attempts at coping are very understandable, but they have the unfortunate disadvantage that they maintain PTSD.
You've used this model to produce a new highly effective form of cognitive behavioural therapy to treat people with persistent PTSD. How does this therapy that you have developed fit in with the model of persistent PTSD that you've described?
With every patient we look individually at how these three factors contribute to their PTSD. In particular we find out what the personal meanings are of the moments from the trauma that come back in the form of flashbacks. Then we work with them at "updating" these memories, bringing into the memory information they have now that can make the flashbacks less threatening. For example, if a flashback to a certain moment of the trauma gives the patient the impression that they are about to die, they could bring in the information that they actually didn't die and still live with their children. We also work on responding differently to trauma reminders and on changing their ways of coping with the memories.
Is it in any way possible to predict who might develop short term or long term PTSD in response to a traumatic event?
Yes, the three factors I described – trauma memory, personal meanings, and unhelpful coping strategies – predict quite well who will have PTSD in the long term. We have confirmed this in studies of people traumatised by many different events, such as assault, traffic accidents, or bombings. We've also investigated whether it is possible to identify vulnerable people even before they experience a traumatic event. For example, we took measures before emergency workers started their training and used them to predict who developed PTSD or depression two to four years later, when they had come across horrible events at work such as the aftermath of accidents and suicide. Again, the same three factors were predictive.
You also study two other anxiety disorders – panic disorder and social anxiety disorder. How do these two disorders differ from PTSD?
In panic disorder, people have sudden attacks of anxiety. These patients often avoid any situation where these panic attacks may occur and become very restricted in their everyday life. In social anxiety disorder the problem is that people are afraid that they might do something in public that is very embarrassing and avoid situations where they might be scrutinised by other people.
There are common elements in that our therapeutic work on PTSD, panic disorder, and social anxiety disorder focuses on people's cognitions: their thoughts and how they remember situations give them an exaggerated impression of threat and, therefore, make them anxious. The content of the thoughts differs between the problems though. For example, panic attacks usually start with physical sensations, like the patient's heart would be pounding. The patient then interprets these sensations as a sign that something awful is going to happen, like "I'm going to have a heart attack". This leads to a vicious circle in that these thoughts make them understandably very anxious and make the physical sensations worse. Typical thoughts in PTSD are "I'm a weak person", or "I'm going to be harmed again", and in social anxiety could be "people will find me boring" or "I will come across as ridiculous".
Dear Prof. Ehlers, thank you very much for this very interesting interview!
Interview: Helen Jaques (© AcademiaNet)