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Why some people develop PTSD while others don't

Hello, my name is Chantelle Wiseman and I am a trainee psychiatrist and PhD student who is currently looking to identify risk factors for PTSD. I work at the University of Bristol, but a large amount of my project is also based at Cardiff University too, because I am funded through GW4 - a collaboration of four of the best universities in South England and South Wales (Cardiff, Bristol, Bath and Exeter). This means I get lots of support from the Cardiff University Traumatic Stress Research Group - Professor Jon Bisson is on my supervisory team, and I meet with the whole team at their research meetings every few months.

People sometimes wonder why I bother with my research because we know what causes PTSD- it’s not called Post-Traumatic Stress Disorder for nothing! We know that PTSD is a disorder caused by a trauma: a trauma is a terrible experience (or repeated experience). It can result in people having a number of symptoms, particularly around re-experiencing of the terrible event (nightmares, recurrent horrible thoughts, feeling like the experience is happening again), but also other experiences such as changes to sleep, avoidance of reminders of the initial event, hypervigilance (being constantly ‘on edge’) and increased startle (being very ‘jumpy’).

However, we also know that not everyone who experiences a terrible event or trauma (such as a near-death experience, sexual assault, or repeated abuse) will get PTSD; most people who suffer an awful event will be affected initially, but only some will go on to develop the full spectrum of PTSD. My research tries to work out why some people may be more vulnerable to PTSD than others. Currently, I am looking at a potential risk factor called social cognition. This is a term that describes how well we can understand our own feelings and emotions, and why we behave the way we do, but also how we understand other people’s emotions and behaviours too. My hypothesis is that if someone has problems with social cognition, they may be more vulnerable to getting PTSD after they have been exposed to a traumatic event, and that their response to treatment will not be as good. A recent review of the published literature found an association between problems with social cognition in patients with PTSD1.

Along with my supervisors, I have designed some experiments to test my hypothesis. Firstly, I am going to use data from a large study in Bristol called the ALSPAC study; data on 14 000 individuals has been collected over the last 30 years, and using this amazing resource I can look to see if problems with social cognition (measured in childhood) are related to PTSD when the children grow up to be young adults.

My second main study involves patients with PTSD. In the next few months I am going to recruit patients from The Traumatic Stress Service in Cardiff, and the equivalent service in Bristol. I will complete some tests of social cognition before the participants start their PTSD treatment. Once they have finished their treatment, I will then measure how much they have improved. I want to see if problems with social cognition are related to poorer treatment outcomes. I plan to test between 40-50 people.

I am 6 months into my 3-year project at the moment and plan to start these two bigger studies in the next couple of months. Currently I am doing two smaller “preliminary” studies. One involves measuring social cognition in a small sample of healthy people; the reason I am doing this is to trial the tests that I am going to use for people with PTSD, to make sure that they work well together and aren’t too much of a burden on the participants. The second study is a series of focus groups; a focus group is a group interview. I have been running these groups with people with lived experience of trauma and/or PTSD, or other mental health problems. I have been doing this to get the opinions of people who know what it’s like to have a mental illness or have experienced trauma, to see whether my planned testing would be manageable for someone who is currently unwell, and also to get their opinions on the project as a whole. Getting the experience of patients who have been through the diagnosis and treatment for PTSD has been really important for me in this study, to make sure I am asking the right questions and trying to answer them in the right way. These two initial studies are going to improve the way I test people with PTSD in the main study, to make sure that the whole process is as pleasant as possible whilst still getting good quality results.

I hope that by the end of the three years, this project will help to contribute to our understanding of why some people are more vulnerable than others to developing PTSD. If this study does show that there is a relationship between social cognition and PTSD, it could have clinical implications. For example, new therapies may need to be developed that are more tailored to those with social cognition difficulties.


  1. Stevens JS, Jovanovic T. Role of social cognition in post-traumatic stress disorder: A review and meta-analysis. Genes, brain and behaviour. 2019;18:e12518. DOI: 10.1111/gbb.12518.