Simple Hair Test Reveals Stress Levels in Children with Chronic Illness

Researchers at the University of Waterloo in Canada have developed a simple method to assess stress levels in children living with chronic illnesses, potentially identifying those at risk for anxiety and depression. This groundbreaking approach involves testing hair samples for cortisol, a hormone that reflects long-term stress exposure. The study highlights the importance of recognizing mental health challenges faced by children with chronic physical illnesses (CPI), such as type 1 diabetes, juvenile arthritis, and epilepsy.

According to a 2025 study, approximately one in four children globally is affected by a chronic illness, with prevalence estimates ranging from 10% to 30%. Children with CPI often encounter significant emotional and social hurdles, including medication routines, school absences, and lifestyle adjustments. These challenges can contribute to a heightened risk of mental health issues, including anxiety and depression.

In this study, the researchers analyzed hair samples from 244 children aged two to 16 diagnosed with a CPI over a four-year period. Hair samples were collected up to five times, with a 3-centimeter segment cut from the scalp, representing roughly three months of cortisol exposure. Parents completed assessments regarding their child’s mental health symptoms, covering both internalizing symptoms, such as anxiety and depression, and externalizing symptoms, like ADHD and behavioral issues.

The research identified three distinct cortisol patterns among the participants: hypersecretion (68%), characterized by consistently high cortisol levels; hyposecretion (9%), marked by consistently low levels; and hyper-to-hypo (23%), where cortisol levels decreased from high to normal. Children in the hyper-to-hypo category exhibited fewer mental health problems compared to those in the hypersecretion group. Interestingly, those with hyposecretion did not show significant differences in mental health outcomes when compared to the high-cortisol group.

The results suggest that chronically elevated cortisol levels are associated with an increased risk of mental health issues, aligning with previous studies highlighting the detrimental effects of prolonged stress. Other factors, such as higher disability scores, being female, and certain parental characteristics, also correlated with worse mental health outcomes.

Despite its promising findings, the study has limitations. Most participants were from relatively advantaged backgrounds and predominantly White, which may affect the generalizability of the results. Additionally, the absence of a healthy control group limits direct comparisons between children with chronic illnesses and their healthy peers. The wide age range of participants may also mask the specific impacts of puberty on cortisol levels and mental health.

The researchers advocate for the use of hair cortisol testing as a non-invasive, easy-to-collect biomarker to identify children potentially at risk for depression, anxiety, or behavioral issues. This method could enable earlier intervention and targeted support for those with consistently high cortisol levels. Moreover, the study suggests that mindfulness-based interventions may help reduce cortisol levels and improve mental health outcomes in affected children.

Dr. Mark Ferro, a co-author of the study and an associate professor in the University of Waterloo’s School of Public Health Sciences, emphasized the importance of early identification of risk factors. He stated, “Identifying these risk factors early could help doctors and families intervene before emotional and behavioral difficulties take hold.”

The findings were published in the journal Stress and Health, marking a significant advancement in understanding the interplay between chronic illness, stress, and mental health in children. As this research gains traction, it holds the potential to transform how healthcare providers approach the mental well-being of children living with chronic health conditions.