Childhood stress hormones reflect chronic adversity in Palestinian territories

Children growing up in active conflict zones experience persistent stress that alters their biology, presenting measurable differences in their morning hormone levels. A study of Palestinian boys revealed substantial trauma exposure across both the Gaza Strip and the West Bank, alongside unique regional patterns in how their bodies produce stress hormones. The research was published in the journal Psychoneuroendocrinology.

Millions of children currently reside in areas affected by armed conflict and political violence. Prolonged exposure to such environments creates persistent psychological strain. This sustained pressure affects developing bodies just as much as developing minds. For decades, researchers have studied how chronic adversity alters human physiology.

When humans encounter an environmental threat, a specific biological network activates within the brain and the body. This network regulates how the body manages high-pressure situations. A central feature of this biological network is the production of cortisol, a primary stress hormone. A healthy human body normally experiences a measurable spike in cortisol shortly after waking up in the morning.

This early morning biological process acts as a preparatory mechanism. The hormone surge helps a person gather the energy needed to face the expected demands of the upcoming day. In environments defined by chronic insecurity, this morning hormone spike can become entirely dysregulated. Some individuals show an exaggerated biological response to the coming day, while others display an unusually blunted response. A blunted pattern suggests the body has downregulated its internal alarm system after prolonged overstimulation.

Obtaining physiological data from children in active war zones presents extreme logistical challenges. Because of these barriers, very few baseline measurements of early morning stress hormones exist for these populations. Olivier Arvisais, a researcher at the Université du Québec à Montréal, led a team to document these hidden physiological profiles. The team wanted to build an objective biological baseline for a population facing sustained political violence.

The researchers focused on Palestinian boys living in the Gaza Strip and the West Bank. They aimed to record the children’s daily stress hormone levels alongside their subjective feelings of stress. They focused exclusively on boys between the ages of nine and eleven. This narrow age range prevented the heavy hormonal changes of adolescence from interfering with the stress measurements.

The research team recruited 115 boys through community centers in both territories. The sample included 62 children in the Gaza Strip and 53 children in the West Bank. This data collection took place before the subsequent escalation of regional hostilities in late 2023. Fieldwork occurred in the West Bank in December 2022 and in the Gaza Strip in July 2023.

Local psychologists and trained social workers conducted one-on-one verbal interviews with the participants. The adults asked the children about their recent exposure to life-threatening situations and violence. They also asked the children to rate their perceived levels of daily stress. Parents were not present during the interviews to ensure the boys provided answers without external influence or social pressure.

The research team took specific steps to ensure their psychological measurements were culturally appropriate. They used a professional translator to convert standard stress and trauma questionnaires into Arabic. The researchers then collaborated with academic experts and local field workers in the Palestinian territories to review the translated text. They modified certain questions to ensure the terminology accurately reflected the distinct cultural contexts of the children’s daily lives.

The psychological surveys yielded sociodemographic details that highlighted distinct living conditions in the two regions. Children in the Gaza Strip reported living in households with a larger number of family members and having more brothers compared to children in the West Bank. The surveys also showed that paternal employment rates were lower in the Gaza Strip. However, maternal employment rates and the overall perceived quality of parent-child relationships were largely similar across both groups.

To measure physiological stress, the research team relied on a decentralized, home-based testing method. The children received detailed language instructions and color-coded medical supplies. Each participant was asked to spit into a small plastic tube immediately upon waking up. Thirty minutes later, they spit into a second tube. The children repeated this biological sampling protocol for three consecutive days to establish a reliable average.

Transporting biological materials across borders was impossible owing to political and logistical restrictions. The research team had to rely on independent local laboratories in each territory to analyze the saliva samples. The samples were transported on dry ice and frozen until laboratory technicians could measure the hormone concentrations.

The initial survey data revealed that children in both regions experienced massive exposure to traumatic events. The participants reported high levels of perceived stress compared to common reference datasets of children living in the United States. A descriptive statistical comparison between the two groups of boys showed that subjective feelings of stress were relatively uniform across both Palestinian areas.

The physiological data presented a varied picture of biological adaptation. In the Gaza Strip, the children displayed a pronounced early morning hormone spike. Cortisol levels rose by an average of 159 percent in the thirty minutes after awakening. This average increase far exceeds the typical 38 to 75 percent growth observed in community samples of children unexposed to major trauma.

Such high morning cortisol levels might reflect an exaggerated biological preparation for expected daily threats. In contrast, the children residing in the West Bank displayed an average morning hormone increase of about 35 percent. While this regional average aligns closer to standard physiological expectations, the individual results varied widely. Some boys in the West Bank showed massive morning cortisol spikes, while others showed muted responses.

When the researchers compared the subjective psychological data to the objective biological data, a specific correlation emerged in the West Bank sample. Boys in the West Bank who reported feeling a deeper emotional impact from their traumatic experiences also exhibited higher early morning cortisol output. This correlation suggests that individual emotional distress translated directly into an anticipatory biological stress response upon waking up.

In the Gaza Strip sample, this specific correlation between perceived trauma severity and morning cortisol spikes did not appear. The lack of a statistical link might indicate that varying types of chronic adversity shape biological stress systems in distinct ways. The boys in Gaza reported different types of daily trauma compared to the boys in the West Bank, experiencing different family structures and distinct economic realities.

The researchers noted multiple caveats regarding their methodology. Because the study only examined prepubescent boys, the patterns cannot be generalized to girls or older teenagers. Additionally, the study represents a single snapshot in time. A cross-sectional design prevents researchers from proving cause and effect, meaning they cannot definitively state that specific traumatic events directly caused the altered hormone levels.

The methodology also faced unavoidable real-world constraints. Because the researchers had to process the saliva samples in two completely separate laboratories, they could not conduct a direct statistical comparison of hormone levels between the two regional groups. Any apparent difference in absolute cortisol values between the Gaza Strip and the West Bank might partly reflect specific laboratory equipment differences rather than sheer biological destiny.

Future research on childhood stress in conflict zones will need to track participants over consecutive years. Observing physiological changes over the course of a child’s development provides a better picture of how bodies adapt to sustained environmental threats. Incorporating biological tests that measure long-term hormone accumulation, such as hair sample analysis, could also improve scientific understanding.

Sustained investigations would benefit greatly from the inclusion of female participants, who may exhibit unique patterns of stress adaptation. Expanding the sample size and improving the collection methods will help scientists establish firmer conclusions. The current findings continue to build an essential baseline for understanding how chronic adversity biologically affects developing children.

The study, “Trauma Exposure, Perceived Stress and Morning Cortisol Levels among Palestinian Boys in the Gaza Strip and West Bank,” was authored by Olivier Arvisais, Catherine Raymond, Mohamed Amine Mahhou, Jonathan Bluteau, Amjad Joma, Sophie Mc Mullin, and Yasser Abu-Jamei.