Exploring War Exposure, Post-traumatic Stress Symptoms and Biological Stress in Syrian Refugee Children 

Background 

War has a significant impact on children’s biological stress levels

Beyond the visible destruction of war, conflict also disrupts a child’s developing brain and body, affecting how they respond to stress in the future. A key part of the body’s stress response system is the hypothalamic-pituitary-adrenal (HPA) axis which controls the release of cortisol, a stress-regulating hormone. Alterations in cortisol levels have been linked to traumatic experiences and post-traumatic stress disorder (PTSD). However, research on how war exposure influences long-term cortisol levels in children remains limited. This study examines how war exposure, living conditions, and post-traumatic stress symptoms are linked to cortisol levels in Syrian refugee children, potentially affecting their risk of long-term mental health challenges. 

 

What were the aims of this study? 

Exploring the long-term biological effects of war in Syrian children and adolescents

This study aimed to investigate whether Syrian refugee children’s post-traumatic stress symptoms, living conditions and exposure to war-related trauma was associated with long-term changes in their stress hormone levels (measured by hair cortisol concentration) using regression analysis.  

 

How was this study carried out? 

A longitudinal observational study involving 1591 children and adolescents 

The study followed 1,591 Syrian refugee children and adolescents (aged 6-18) living in informal settlements in Lebanon as part of the Biological Pathways of Risk and Resilience in Syrian Refugee Children (BIOPATH) project. Data were collected over two years (2017-2019), with stress hormone levels measured from hair cortisol concentrations (HCC) – a method assessing long-term cortisol secretion. 

Children and their caregivers were asked about war-related experiences, including exposure to violence, bombings, and forced displacement. PTSD symptoms were also measured using a standardised questionnaire. Researchers then used statistical models to explore links between war exposure, PTSD symptoms, and cortisol levels while accounting for factors like age, sex, current living conditions and time since leaving Syria. 

 

What were the key findings? 

Adolescence may be a particularly vulnerable period for stress-related biological changes, which can evolve over time

Results revealed several key findings indicating the lasting physiological effect war has on children. 

1. Firstly, children with more PTSD symptoms and war exposure had increased HCC. Increased cortisol was, however, limited to children who were 12 years or older at the time of war exposure. This is unlike PTSD symptoms, which were associated with HCC regardless of age and war exposure. 
2. The time since displacement is shown to be significant. When the 0 to 12 months since displacement group were compared to the 12 months and more group, findings showed that the longer a child were away from Syria, the lower their cortisol levels. This suggests that stress responses might decline over time.  
3. Interestingly, the quality of current living conditions (e.g., access to food, housing) did not significantly affect cortisol levels. This indicates that past trauma may have a stronger influence on stress regulation than present-day challenges.  

 

What are the implications of this research? 

Long-term mental health support is required for young refugees who have lived through war

This study provides novel insights into how war exposure leaves a lasting biological imprint on Syrian refugee children and adolescents and raises important questions on how best to support young refugees. Understanding the relationship between war exposures, time since leaving Syria, PTSD symptoms and cortisol levels can help shape improved humanitarian interventions. This is specifically necessary for adolescents who appear more vulnerable to trauma-related stress changes.  

The findings, which show no clear evidence of the impact of specific types of war-related events, suggest that this research could be more broadly applied to children displaced by conflict worldwide. By understanding how trauma affects the developing body and brain, we can better support refugee children. However, further questions remain regarding the duration of cortisol disruptions in the HPA-axis and whether these disruptions contribute to mental health issues later in life. 

 

About the study team  

The study was conducted by a team of experts in psychology and mental health including; Dr Demelza Smeeth, Dr Fiona S. McEwen, Dr Cassandra M. Popham and Prof Michael Pluess from Queen Mary University of London; Prof Elie Karam, Prof John Fayyad and Dahlia Saab from Balamand University and IDRAAC; Dr Michael Rieder, Dr Abdelbaset A. Elzagallaai and Dr Stan van Uum from University of Western Ontario.