Researchers at the University of Waterloo wanted to know whether measuring stress hormones in children's hair could predict mental health problems in kids living with chronic physical illnesses—conditions like diabetes, asthma, or arthritis that last a long time.
The study followed 244 Canadian children with chronic illnesses over four years, taking hair samples to measure cortisol, a hormone released when the body experiences stress. More than two-thirds of these children had persistently high cortisol levels throughout the study period.
Children with rising stress showed more anxiety and depression
The key finding: children whose cortisol levels stayed elevated over time were significantly more likely to develop symptoms of depression, anxiety, and behavioral difficulties compared to children whose stress levels decreased. This suggests that long-term stress—not just stress in the moment—matters for mental health outcomes.
The researchers emphasized that living with a chronic illness creates constant emotional strain: managing medications, missing school, and adapting daily activities all take a psychological toll. For many children, this accumulates into serious mental health challenges.
A simple test that could catch problems early
What makes this research promising is the method itself. Hair cortisol is non-invasive—a few strands collected painlessly—and it reflects stress levels over months, not just a single day. This makes it potentially useful as a screening tool in clinics. Doctors could use it to identify which children with chronic illnesses need mental health support before problems become severe.
However, it's important to note this study was conducted in Canada with a specific group of children. While the findings are encouraging, the approach would need testing in other populations, including Singapore, before becoming standard practice in local healthcare settings.
Early intervention could reduce long-term harm
Children with chronic illnesses already face higher risks of poor quality of life and mental health crises. Catching those at greatest risk early—through a hair test—could allow families and doctors to provide targeted support before depression or anxiety takes hold. The study suggests this biological marker could eventually help track whether treatments and support programs are actually reducing a child's stress over time.