What Children's Hair May Reveal About Their Mental Health

How children and adults wear their hair can certainly be a sign of many things: their personal style, their level of focus on external appearances, or simply how much time they have in the morning. Often, in cases of high stress or depression, grooming and hygiene fall by the wayside: fewer showers; exhaustion that gets in the way of combing one's hair; or even self-esteem taking enough of a hit that someone stops looking in a mirror altogether.

What gets far less attention is how the actual make-up of a single strand of hair may itself hold some important clues about mental health.

But new research from the University of Waterloo suggests that this is an avenue worthy of exploration.

This latest study, led by E. Littler, Z. Butt, A. Gonzales, and M. Ferro, examined Canadian children, 2 to 16 years old, who live with chronic physical illness. This is a population that is growing over time and is significantly at risk of experiencing mental health challenges as compared with children without chronic physical illness.

The 244 children involved in the study were followed for four years, and their hair cortisol levels were examined over time. This measurement is referred to as hair cortisol concentration (HCC). Cortisol, the naturally occurring stress hormone that is elevated in times of sustained or intense stress, is often assessed via saliva or a blood sample, but measuring it in hair is significantly less invasive.

Among this population of children, three patterns of cortisol levels over time were identified: high to low, consistently high, and consistently low. Strikingly, more than two-thirds of the children studied showed consistently high cortisol levels. And most significantly, those same children exhibited higher rates of mental health concerns, including depression and anxiety, than the children whose cortisol levels were not consistently high.

And in turn, the study participants whose hair cortisol levels showed declines—going from high to low—were less likely to have symptoms of behavior problems, depression, or anxiety than the other groups.

All this from a strand of hair?

What makes this line of research particularly striking is that it could potentially identify children in advance who carry a higher risk for mental health difficulties. Of course, whether high hair cortisol concentration is caused by stressful life experiences that raise overall cortisol levels, psychological processes that make certain children less able to manage stressful life experiences without a physical toll being taken, a genetic susceptibility to higher cortisol or some combination of all of these, the bottom line is the same: a child's HCC may predict their future well-being.

Does this apply to children without chronic physical illness? That's another question for future research to sort out. But the potential for strands of hair to be used to help identify and support high-risk children, without the need for a blood draw or extensive psychological testing, is very promising indeed.