War not only traumatizes children, it dramatically reshapes their DNA

The ongoing war between Ukraine and Russia and the Israeli-Palestinian conflict have plunged millions into a humanitarian crisis, displacing families and exposing children to relentless violence and instability.

The psychological toll of witnessing the horrors, loss, fear and uncertainty of war has been widely acknowledged, but emerging research suggests the damage runs even deeper.

Groundbreaking research from the University of Surrey highlights how war affects children at a biological level, changing their DNA through a process called DNA methylation.

These changes could have lifelong implications for their mental and physical health, revealing the hidden costs of war on the youngest and most vulnerable victims.

The biological impact of war on children

The first research of its kind, published in JAMA Psychiatryinvolved saliva samples from 1,507 Syrian refugee children, aged 6 to 19, living in informal settlements in Lebanon.

The researchers looked at DNA methylation (DNAm), an epigenetic process that modifies DNA by adding chemical tags that can activate or silence genes without changing the underlying genetic code.

This means that DNAm changes could increase vulnerability to anxiety, depression and post-traumatic stress disorder (PTSD) by affecting the brain’s ability to process and regulate emotions or by increasing sensitivity to stress.

Physically, children may have weakened immunity, are at risk of chronic inflammation or slower physical development, as seen in children exposed to trauma such as war.

To assess war-related trauma, questionnaires were completed by both children and their caregivers.

In collaboration with University College London, Lebanese research institutions and an international NGO, the team discovered DNAm changes in children exposed to war events. These changes were found in genes responsible for critical functions such as neurotransmission (nerve cell communication) and intracellular transport (movement of materials within cells).

Interestingly, the study revealed that these DNA changes are specific to war trauma and differ from those caused by other adversities such as poverty or aggression.

Lead researcher Professor Michael Pluess from the University of Surrey explained: “Our findings show that war impacts children not only mentally but also biologically. We observed slower epigenetic aging in these children, indicating that the war could also affect their development.”

He added: “This study sheds light on the wider and tragic cost of war on the millions of children who are caught in its grip.”

Key insights from the BIOPATH study

Part of the BIOPATH study, which began in 2017, this research marks a milestone in understanding the long-term impact of trauma on refugee children. The study also revealed notable gender differences.

Girls exposed to war events showed more significant mRNA changes than boys, particularly in genes related to stress response and brain development. This suggests that girls may be more biologically vulnerable to the long-term effects of trauma.

DNA methylation is a natural process in which methyl groups are added to DNA, acting as switches that regulate gene activity. Although essential for normal development, DNAm can be influenced by environmental factors such as stress and trauma.

Severe experiences such as war can alter DNAm patterns, leaving lasting biological imprints on mental and physical health.

The findings provide a deeper understanding of how extreme stress reshapes the biology of children in war zones.