Sanne van der Wal PhD dissertation defence ‘At mission’s end. The long-term impact of deployment on mental health’

On the 13th of December 2022, Sanne van der Wal successfully defended her PhD dissertation and obtained the degree of Doctor at the Leiden University.

Proefschriftcover Sanne J. van der Wal

Sanne van der Wal has been working at the Brain Research and Innovation Centre as a PhD student since 2017. She investigated the prevalence figures for various psychiatric symptoms ten years after deployment to Afghanistan (the PRISMO study), as well as the course of these complaints over time. In addition, she was involved in the identification of risk and protective factors for the development of psychological complaints.

It was already known that military deployment could lead to mental health issues in veterans, but the long-term impact was yet unknown. In this dissertation, the results from the PRISMO study are discussed. This is a large prospective cohort study in a group of Dutch Afghanistan veterans with a follow-up period of ten years. Although the majority of the veterans did not develop any psychiatric symptoms after deployment, the results show that 10 years after deployment, about 8% of the veterans still suffered from posttraumatic stress disorder (PTSD) symptoms. Furthermore, the prevalence of agoraphobia, anxiety, depression and hostility symptoms was higher than before deployment. Additionally, the results show large individual differences in the development and trajectory of the PTSD-symptoms over time. A group of 7% showed a delayed trajectory of increasing symptoms, and only reached the cut-off for PTSD between two and five years. Between five and ten years post-deployment, their symptoms were still increasing, although 77% of this group received some form of psychological care in the years after deployment. A decade after their deployments, we should especially be aware of this group of veterans.

The results from this dissertation also showed that, beyond the traumatic experience itself, individual vulnerability factors can contribute to developing mental health symptoms. For example, perceived social support and biological factors, such as DNA-methylation, were associated with the development of PTSD and other psychiatric symptoms after deployment. As of yet, the combination of these risk factors has not led to the development of effective pre-deployment screening tools. The results do provide important starting points for identifying risk factors for PTSD and developing resilience-building initiatives to prevent or reduce symptoms. 

On the 13th of December 2022, Sanne van der Wal successfully defended her PhD dissertation and obtained the degree of Doctor in the Academiezaal at the Leiden University.

Click here to view her dissertation.