Testing for cortisol in hair samples may one day aid in the diagnosis of depression and in efforts to monitor the effects of treatment, according to a new study published online in the journal Psychoneuroendocrinology.
Researchers from The Ohio State University looked for potential links between the concentration of the stress hormone cortisol in the hair and depression symptoms in teens and found a surprising connection.
Not only did they find higher levels of cortisol to be linked to a greater risk for depression, but they also found a link between low cortisol levels and mental health issues.
Though several studies have used cortisol measures to gauge mental health in the last decade, few have looked at the stress hormone as a predictor of depression. Those who have found mixed results, so the new study adds important information, said Jodi Ford, Ph.D., R.N., lead author of the study and an associate professor of nursing at The Ohio State University.
In the clinical setting, a biomarker-based test for depression would be valuable, particularly for children and teens, she said.
“This study opens up a lot of future research questions and illustrates that the relationship between cortisol levels and depression isn’t necessarily a linear one,” Ford said.
“It may be that low cortisol is bad and high cortisol is bad and there’s a middle level that is normal,” she said. “It’s hard to know why this is without more research, but it’s possible that there’s a blunting of the stress response in some people, lowering cortisol production or changing how it is processed. Maybe the body is not using cortisol in the way that it should in some cases.”
The researchers also found that adolescents who said they felt better supported at home had much lower levels of depressive symptoms.
“This study reinforces to parents that they matter in their adolescents’ lives, that their support and involvement make a difference,” said Ford, who also directs the Stress Science Lab in Ohio State’s College of Nursing.
The study involved 432 adolescents (ages 11 to 17) who were enrolled in the larger ongoing Adolescent Health and Development in Context study, a research project focused on the impact of social experiences and other factors on health. That project is led by Dr. Christopher Browning, a sociology professor at Ohio State who is also a co-author of the cortisol and depression study.
For the cortisol study, the research team measured depression with a nine-item questionnaire. The teens were asked to rate their experiences in several areas, including how often they feel that their life has been a failure or that people have been unfriendly to them.
In most cases, the researchers examined a 3-centimeter hair sample — enough to determine cortisol levels for the previous three months.
After adjusting the results for other factors that could contribute to depressive symptoms and cortisol levels, the researchers discovered the surprising trend that both low and high cortisol had a statistically significant link to depression.
“It’d be really ideal to have an objective measurement, because using subjective measures of stress is problematic, particularly with children and teens,” she said.
The test is simple, and relatively cheap (on the order of about $35), but it won’t be something to consider for widespread use until researchers better understand what values are normal and what values are out of range and cause for concern, Ford said.
Apart from being a detection tool, hair testing could also be a way to see if therapy and medication are helping someone with depression over time, or if the mental illness is intensifying and putting the adolescent at risk of suicide, she said.
Source: The Ohio State University