Measuring stress levels through hair samples could provide important clues about mental health risks in children living with chronic physical illnesses, research suggests.

“Hair cortisol offers a non-invasive, easy-to-collect biomarker that could one day be used to screen children and track whether treatments or support programs are helping to reduce stress,” study co-author Mark Ferro, a professor in the University of Waterloo’s School of Public Health Sciences, said in a press statement.

An estimated 40 percent of children in Canada live with chronic physical illnesses (CPI)—a number that has been increasing over the past decades.

As George Citroner details below for The Epoch Times, those with higher cortisol levels are more likely to develop mental health problems at rates ranging from 20 percent to 50 percent, significantly higher than the prevalence in healthy children, researchers noted.

These conditions can lead to lower quality of life, suicidal thoughts, and greater use of health care services.

Chronic Illness Linked to Mental Health Difficulties

Published this year in Stress and Health, the study tracked 244 Canadian children with chronic physical illnesses over four years. Researchers used hair cortisol, a biological marker that reflects stress over time, to measure stress levels.

The results showed that more than two-thirds of the children had consistently high cortisol levels.

When comparing these stress patterns to reports of emotional and behavioral difficulties, scientists saw that children whose cortisol levels declined showed fewer symptoms of anxiety, depression, and behavior problems than those whose levels remained high.

Why Hair Testing Matters

Unlike current screening methods that rely on behavioral assessments after problems emerge, hair cortisol testing could identify at-risk children years earlier. The hormone cortisol accumulates in hair over months, providing a long-term picture of stress levels that blood or saliva tests cannot capture.

According to researchers, this discovery could help guide prevention and treatment strategies to better support children’s well-being.

“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. This opens the door to earlier and more targeted support,” lead study author Emma Littler, a University of Waterloo doctoral candidate in public health sciences, said in the press statement.

As hair develops, cortisol from the bloodstream and from secretions of sweat and sebaceous glands becomes embedded within the hair shaft.

Human scalp hair typically grows at a fairly consistent rate of about 1 centimeter per month, which allows a 1 centimeter segment of hair to serve as a reliable indicator of the average stress level during that month.

To create a historical record of cortisol exposure, hair is often sectioned into segments; for instance, a 3-centimeter sample can be divided into three 1-centimeter segments, each representing a separate month. In laboratory analysis, the hair sample undergoes washing to eliminate external contaminants, followed by pulverization and incubation in a solvent such as methanol to extract the cortisol.

The extracted hormone is then measured using highly sensitive techniques such as enzyme-linked immunoassay or liquid chromatography-mass spectrometry. The resulting measurement is expressed as the amount of cortisol per milligram of hair, typically in picograms per milligram.

Dr. Molly McVoy, an associate professor of psychiatry at Case Western Reserve University’s School of Medicine, who was not involved in the study, noted that anxiety and mood disorders such as depression are most commonly associated with chronic medical conditions. She pointed out that in these conditions, changes in cortisol are signs that a child is more at risk for an anxiety or mood disorder.

Warning Signs Parents Should Watch For

McVoy listed specific signs or symptoms parents should watch for in children that might indicate they’re experiencing high stress or they have mental health concerns.

“I recommend parents think about what their [kids are] supposed to [be] doing at that age,” she added. “Are they able to do it? If not, we wonder what’s getting in the way.”

For example, school-aged children who struggle to learn, make friends, or enjoy those activities—and teenagers who are not engaged with peers—may be showing warning signs of stress or mental health concerns, McVoy said.

Other warning signs include disrupted sleep patterns in children without access to devices that could keep them awake, and the inability to engage in age-appropriate activities.

How to Reduce Stress in Children

McVoy emphasized that children with chronic diseases need their lives kept as “typical” as possible, while acknowledging their different needs.

Do:

• Help them attend school regularly when possible

• Encourage participation in sports and activities they can manage

• Facilitate time with friends

• Maintain healthy sleep and physical activity routines

Don’t:

• Remove all expectations you would have for healthy children

• “Overcompensate” by making life too easy

• Treat them so differently that they feel socially separated from their peers

Parents often overcompensate in how they treat their chronically ill children, by removing all expectations they would have for a healthy child, McVoy said. However, this can make kids feel more stressed and increase feelings of social separation.