Cortisol Identified as Biomarker for Severe Depression in Teenage Boys

A team of British neuroscientists has found a dynamic link between high levels of the hormone cortisol and chronic depression, especially among teenage boys.

Clinical depression is a severe and common illness, characterized primarily by a persistent low mood and lack of pleasure in usually enjoyable activities, which results in significant impairment in everyday living. It also involves alterations in cognitive and hormonal functions. There is substantial variation between depressed individuals in terms of the causes and therapeutic response, making it difficult to identify those most likely to benefit from intervention and treatment.

Cortisol (hydrocortisone) is a glucocorticoid hormone, produced by the zona fasciculata of the adrenal gland. It is released in response to stress and a low level of blood glucocorticoids. Its primary functions are to increase blood sugar through gluconeogenesis; suppress the immune system; and aid in fat, protein, and carbohydrate metabolism.

Investigators at the University of Cambridge (United Kingdom) sought to identify biochemical markers that could be linked to depression. Towards this end, they measured cortisol levels in saliva samples obtained from two groups of teenagers. The first group of 660 provided samples on four school mornings within a week and then again 12 months later. A second group of 1,198 teenagers gave samples over three school mornings. Over the time period, the participants were asked to fill out a questionnaire designed to reveal symptoms of depression.

The participants were separated into four subgroups determined by combining cortisol results with data from the questionnaires. Group I was comprised of individuals with normal levels of cortisol and low symptoms of depression while Group IV was composed of those with elevated cortisol and severe symptoms of depression. Results of the analysis revealed that those in Group IV were on average seven times more likely than those in Group I, and two to three times more likely than in the other two groups, to develop clinical depression. Further analysis showed that boys in Group IV were 14 times more likely to develop clinical depression than those in Group I, and two to four times more likely to develop it than boys in either of the other two groups.

"Depression is a terrible illness," said senior author Dr. Ian Goodyer, professor of adolescent psychiatry at the University of Cambridge. "[And] we now have a very real way of identifying those teenage boys most likely to develop clinical depression. Armed with such knowledge, doctors and other caregivers could target prevention strategies at depression-vulnerable boys and hopefully help reduce their risk of serious episodes of depression and their consequences in adult life."

The study was published in the February 18, 2014, online edition of the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).

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