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Traumatic stress research: The important questions of this time (Part 2)

In part one of this blog, I talked about the recent changes in how the different ways in which people can present after traumatic events are recognised, as reflected in the revised ICD11 criteria for PTSD and the inclusion of CPTSD as a diagnosis. In part two, I will talk about the research questions that the changes have created, and which the National Centre for Mental Health (NCMH) and the Traumatic Stress Research Group (TSRG) at Cardiff University are committed to exploring. These questions include:

  • How can we appropriately diagnose ICD11 defined PTSD and CPTSD?

  • What makes someone more likely to develop PTSD or CPTSD?

  • How can we develop and evaluate effective treatments for PTSD and CPTSD?

How can we appropriately diagnose ICD11 defined PTSD and CPTSD?

As touched on in part one of this blog, there exists ongoing debate over the construct of psychiatric diagnosis. Regardless of your stance on diagnosis, however, there is no denying its role in today’s world.

Clinically, psychiatric diagnosis can help individuals to make sense of their suffering and enable signposting to evidence-based treatments. Without valid and useful psychiatric diagnostic constructs, it would also be extremely difficult to develop an empirically based understanding of human psychological suffering. The construct of diagnosis therefore helps facilitate high quality research and to consequently develop and evaluate treatments which hope to reduce this suffering.

Diagnoses can, however, create more confusion and suffering if given inappropriately. Inaccurate diagnosis can lead to people feeling misunderstood and being referred to unhelpful treatments. It may also result in misguided research which lacks scientific soundness.

In order to assist with accurate psychiatric diagnosis, clinicians and researchers often rely on widely accepted diagnostic measures. A widely-used questionnaire measure and semi-structured interview have been validated for the purpose of assessing DSM-5 defined PTSD (Blevins et al., 2015; Weathers et al., 2013; Weathers et al., 2018, Weathers et al., 2013). However, until recently, no equivalent measures existed for ICD11 PTSD and CPTSD.

In collaboration with colleagues across the globe, researchers from the TSRG at Cardiff University have established the International Trauma Questionnaire, a self-report measure of symptoms of ICD11 PTSD and CPTSD (Cloitre et al., 2018). The brief nature of the ITQ is a particular strength, since it can be easily administered and translated for use across the globe and is now freely available in many different languages (

Face-to-face interviews are, however, considered superior for psychiatric diagnosis. The researchers who developed the ITQ have been working to address the need for such an interview for ICD11 PTSD and CPTSD. The International Trauma Interview (ITI) is designed to be administered by trained individuals to accurately diagnose ICD11 PTSD and CPTSD.

Evidence has already begun to show promise for the usefulness of the ITI as a diagnostic measure (Bondjers et al., 2019). However, in order to further evaluate the ITI and provide sufficient evidence for its validation, more research is needed. The TSRG and NCMH are therefore asking willing individuals who have experienced trauma to take part in research interviews using the ITI. The information gathered from these interviews will help us to further investigate the usefulness of the ITI. Should it be proved sufficiently accurate in diagnosing ICD11 PTSD and CPTSD, it is hoped that the ITI may be used around the world for this purpose. The implications of this, as discussed earlier, would be profound for survivors of traumatic events, clinicians and researchers in the field.

What makes someone more likely to develop PTSD or CPTSD?

Following a traumatic experience, individual reactions will vary greatly. It is thought that this is likely related to a complex interaction between a range of factors. The research underway at Cardiff University hopes to create a better understanding of what specific factors might make someone more likely to develop PTSD, CPTSD or neither disorder.

With regards to CPTSD, ICD11 states that the disorder is more likely to develop following experiences that are ‘extremely threatening or horrific in nature, most commonly prolonged or repetitive events from which escape is difficult or impossible’ (WHO, 2018). It has long been argued that complex presentations are more likely to arise from repeated traumatic experiences early in life which are interpersonal in nature (e.g. Herman, 1992). However, ICD11 recognises that CPTSD may also arise following a single traumatic event experienced in adulthood.

The research at Cardiff University is designed to determine if certain individual factors, such as adverse childhood experiences or having a particular attachment style (way of relating to others in close relationships), may confer greater risk for developing CPTSD or PTSD.

There is also increasing interest in the interaction between an individual’s genetics and their environment. Research hopes to understand whether having a particular genetic make-up may contribute to a vulnerability for developing PTSD or CPTSD following a traumatic experience. Some of those who take part in research with the TSRG and NCMH are therefore asked to provide a blood or saliva sample. Genetic analysis of these samples will help us to identify whether there exist specific genes which may be involved in this interaction.

Through developing our understanding of what might make someone more likely to develop a particular set of symptoms following a traumatic experience, this may help us to predict trajectories of the disorder and have implications for treatment and prevention of symptoms of traumatic stress.

How can we develop and evaluate effective treatments for PTSD and CPTSD?

The ICD11 revisions mean that we are now better able to evaluate interventions which specifically address the distinct symptom profiles of ICD11 defined PTSD and CPTSD. Such research will no doubt be embraced by survivors of traumatic experiences, some of whom may have found existing treatments unhelpful, as well as by the clinicians who wish to offer the most effective interventions.

In the UK, the National Institute for Health and Care Excellence (NICE) provide advice and guidance on the provision of health and social care based on the highest quality evidence available. In their most recent PTSD publication in 2018, NICE reviewed the evidence concerning interventions to prevent and treat PTSD (NICE, 2018). Interventions with an existing strong evidence base were retained in the guidelines, including Eye Movement Desensitisation Reprocessing (EMDR) and trauma-focused Cognitive Behavioural Therapy.

A new addition to the guidelines was computerised trauma-focused cognitive behavioural therapy (CTFCBT). This is particularly exciting for researchers at Cardiff University, who have been involved in developing and evaluating such an intervention using the most rigorous scientific methods. Evidence from the Cardiff University work contributed to CTFCBT being recommended (Lewis et al., 2017. See also Simon et al., 2019 for an up-to-date systematic review of the acceptability of internet-based CBT interventions for PTSD).

NICE were unable to provide guidance on the management of CPTSD, due to the limited evidence available at the time. They did, however, provide some considerations for the management of complex presentations, such as allowing for a longer duration of treatment and acknowledging the potential for a greater number of barriers to the success of traditional treatments for PTSD (NICE, 2018).

In the absence of comprehensive guidance for the management of CPTSD, The International Society for Traumatic Stress Studies (ISTSS) compiled a position paper (ISTSS, 2018). This paper, contributed to by members of the TSRG, reviews the current state of our understanding of CPTSD, how best to develop an evidence base for its treatment, as well as recommendations for future research.

The ISTSS guidelines mention how treatment protocols for CPTSD will likely benefit from the addition of interventions which directly address the disturbances in self organisation by which the disorder is characterised. Research conducted by the TSRG and colleagues has supported this, for example suggesting that existing psychological treatments for PTSD may benefit from cultivating self-compassion in light of a persistently negative view of the self (Karatzias et al., 2019).

Although there exists much evidence for trauma-focused CBT and EMDR for PTSD, once the hurdle of diagnosis has been overcome, accessing these treatments can be an even bigger struggle. EMDR and trauma-focused CBT are highly specialised interventions, which typically require committing to weekly sessions with a trained clinician over the course 8-12 weeks (NICE, 2018). Given the specialised nature of these interventions and the time commitment required, such interventions are, sadly, not readily available to the many individuals who may benefit from them. It is, therefore, imperative that we continue to explore alternative interventions for PTSD, such as computerised trauma-focused CBT, which may be more easily accessed by a larger number of individuals.

The Rewind technique is another intervention which has some emerging evidence for treating symptoms of PTSD in as little as one session (Muss, 1991; Adams & Allan, 2018). In order to provide evidence for such an intervention to be included in national guidance and to be made widely available, further research is required in the form of a randomised-controlled trial. If proved effective, the Rewind technique has promise as a cost-effective intervention which has the potential to be much more readily accessed than highly specialised and lengthy existing interventions for PTSD. The TSRG will soon start a randomised controlled trial of Rewind that should help to determine its likely efficacy.


The ICD11 revisions represent a pivotal point in the field of traumatic stress research. They simultaneously show how far we have come in our understanding of traumatic stress, yet also highlight the desperate need for further research in order to ease the confusion created by the discrepancy they create with DSM-5. By exploring the questions discussed, it is hoped that we can contribute to improved understanding, diagnosis and treatment of disorders of traumatic stress and ultimately reduce the suffering of those experiencing such.

Personally, I have been truly inspired by the passion and determination of the traumatic stress researchers at Cardiff University to answer the most pressing questions of this time. With much invaluable teaching and guidance, my role in the collaboration between NCMH and the TSRG has been to conduct research interviews with survivors of traumatic experiences, which will help us to answer some of the questions I have highlighted.

In conducting these interviews, I have felt extremely humbled by the willingness of those who have experienced trauma to take part in research for the most selfless of reasons; to share their experiences in the hope of improving the lives of others in the future. The most crucial collaboration, then, is with the survivors of traumatic experiences themselves, without whom the research would not be possible at all.


Adams, S., & Allan, S. (2018). Muss’ rewind treatment for trauma: description and multi-site pilot study. Journal of Mental Health, 27(5), 468-474

Blevins, C.A., Weathers, F.W., Davis, M.T., Wittle, T.K., & Domino, J.L (2015). The Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5): Development and initial psychometric evaluation. Journal of Traumatic Stress, 28, 489-498

Bondjers, K., Hyland, P., Roberts, N.P., Bisson, J.I., Willebrand, M., & Amberg, F.K. (submitted for publication). Validation of a clinician-administered diagnostic measure of ICD-11 PTSD and complex PTSD: the international trauma interview in a Swedish sample. European Journal of Psychotraumatology

Cloitre, M., Shevlin, M., Brewin, C.R., Bisson, J.I., Roberts, N.P., Maercker, A., Karatzias, T., Hyland, P. (2018). The International Trauma Questionnaire: development of a self-report measure of ICD-11 PTSD and complex PTSD. Acta Psychiatrica Scandinavica, 138, 536-546

Herman, J. (1992). Trauma and recovery. New York: Basic Books

International Society for Traumatic Stress Studies (2018). Position paper on complex PTSD in adults. Retrieved from

Karatzias, T., Hyland, P., Bradley, A., Fyvie, C., Logan, K., Easton, P., Thomas, J., Philips, S., Bisson, J.I., Roberts, N.P., Cloitre, M., & Shevlin, M. (2019). Is self-compassion a worthwhile target for ICD-11 complex PTSD (CPTSD)? Behavioural and Cognitive Psychotherapy, 47(3), 257-269

Lewis, C.E., Farwell, D., Groves, V., Kitchiner, N., Roberts, N., Vick, T., Bisson, J. (2017). Internet-based guided self-help for post-traumatic stress disorder (PTSD): randomised controlled trial. Depression and Anxiety, 34, 555-565

Muss, D.C. (1991). A new technique for treating post-traumatic stress disorder. British Journal of Clinical Psychology, 30(1),

National Institute for Health and Care Excellence (2018, December). Post-traumatic stress disorder NICE guideline [NG116]. Retrieved from

Simon, N., McGillivray, L., Roberts, N.P., Barawi, K., Lewis, C.E., & Bisson, J.I. (2019). Acceptability of internet-based cognitive behavioural therapy (i-CBT) for post-traumatic stress disorder (PTSD): a systematic review. European Journal of Psychotraumatology, 10(1), doi: 10.1080/20008198.2019.1646092

World Health Organization (2019). International Statistical Classification of Diseases and Related Health Problems (11th ed.).

Weathers, F.W., Blake, D.D., Schnurr, P.P., Kaloupek, D.G., Marx, B.P., & Keane, T.M. (2013). The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5). [Assessment]

Weathers, F.W., et al. (2018). The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5): Development and initial psychometric evaluation in military veterans. Psychological Assessment, 30, 383-395

Weathers, F.W., Litz, B.T., Keane, T.M., Palmieri, P.A., Marx, B.P., & Schnurr, P.P. (2013). The PTSD checklist for DSM-5 (PCL-5).