Researchers at Cambridge University in the United Kingdom report that they have found that adolescent boys can be identified as high risk for developing clinical depression based on levels of cortisol in their saliva in combination with behavioral symptoms of depression. This new work, published in a paper in the Proceedings of the National Academy of Sciences on February 18th (edited by Foundation Scientific Council member Bruce S. McEwen, Ph.D.), offers the possibility of a biomarker, or biological predictor, to identify youths at risk and enable interventions at the early stages of illness.
Psychiatric diagnoses, including those for depression, generally rely upon a clinician’s (psychiatrist’s) insight and observation of behavioral symptoms. To date, there are very few means by which an individual’s biology can accurately predict or confirm the presence of psychiatric illness. Some gains are being made using brain imaging techniques, and some work has been done linking inflammation to depression, but the complex biology and functioning of the brain has made it very difficult to establish definitive biomarkers for psychiatric illness.
This new work, led by 2002 NARSAD Distinguished Investigator Grantee, Ian Goodyer, M.D., combined self-reported measurements of depressive symptoms with early-morning cortisol levels in a sample of 1,858 teenagers to determine if there was any association between these two measurements and later development of depression. After taking the measurements, they checked back in with each teenager 12 to 36 months later to determine which individuals had developed major depression and other mental illnesses. They found that the boys with both high self-reported depressive symptoms and high cortisol levels in their saliva were 14 times more likely to suffer from major depression than those with normal levels of cortisol and low symptoms of depression.
Dr. Goodyer, Professor in the Department of Psychiatry at Cambridge University, told the Irish Independent: “Through our research, we now have a very real way of identifying those teenage boys most likely to develop clinical depression.” He continued, “This will help us strategically target preventions and interventions at these individuals and hopefully help reduce their risk of serious episodes of depression and their consequences in adult life.”