Hair Cortisol Levels May Signal Mental Health Risks for Children with Chronic Illnesses
New research from the University of Waterloo suggests that measuring cortisol levels in hair samples could be a valuable tool for identifying children with chronic physical illnesses (CPI) who are at higher risk of developing mental health problems. The study, published in Stress Health (2025;41(4):e70087, doi: 10.1002/smi.70087), found a strong correlation between persistently high cortisol – a hormone released in response to stress – and increased symptoms of depression, anxiety, and other mental health concerns.
Approximately 40% of Canadian children currently live with a CPI, a number that has been consistently increasing. Children with CPI are known to be at elevated risk for mental health challenges, possibly leading to a diminished quality of life, suicidal thoughts, and greater reliance on healthcare services.
The study followed 244 Canadian children with chronic physical illnesses for four years, utilizing hair cortisol as a biomarker to assess long-term stress levels. Researchers discovered that over two-thirds of the children exhibited consistently high cortisol levels. Importantly, these children were significantly more likely to display symptoms of mental health difficulties compared to those whose cortisol levels decreased over the study period.
“Our findings suggest that chronically high stress, measured through hair samples, could help identify children with CPI at the highest risk for developing mental health problems,” explained Emma Littler, a Waterloo PhD candidate in Public Health Sciences and lead author of the study. “This opens the door to earlier and more targeted support.”
The research also demonstrated a positive impact of decreasing cortisol levels. Children whose cortisol levels declined over time reported fewer symptoms of anxiety, depression, and behavioral problems.
Dr. Mark Ferro, a professor in Waterloo’s School of Public Health Sciences and co-author of the study, emphasized the potential for proactive intervention. “Identifying these risk factors early could help doctors and families intervene before emotional and behavioural difficulties take hold,” he stated. he also highlighted the practicality of hair cortisol as a “non-invasive, easy-to-collect biomarker” that could potentially be used for screening and monitoring the effectiveness of treatments and support programs.
This research was originally published by the University of Waterloo and has been republished by Technology Networks.
