A new study has been released that potentially reveals the onset of depression with just a few globs of spit and a successfully filled questionnaire. It was found that teenage boys with high levels of the stress hormone cortisol in their saliva are 14 times more likely to develop depression; thus the study has found the first biological marker to accurately predict the risk of the disease.
Around the world, depression is one of the leading causes of disability. It takes hold early in life: half of all cases begin by age 14, and three-quarters by age 24 reports Catherine de Lange of NewScientist Health.
It is hoped by Barbara Sahakian at the University of Cambridge, one of the study's authors, that the finding could lead to new pharmacological treatments for depression and could change the way schools deal with the condition. Teenagers could be screened for the biomarker and those at risk provided with targeted treatments.
Her team measured morning levels of cortisol over three days in 660 teenagers aged between 13 and 18. Elevated levels of this hormone have previously been implicated in depression. The team also recorded any pre-clinical depressive symptoms the teens reported over a year, such as tearfulness or lack of motivation. The study was later repeated in a group of about 1200 teens.
Teenage boys who reported high levels of depressive symptoms, and had high levels of cortisol, were more likely to have become clinically depressed over the next three years than any other combination. Those in this high risk group were 14 times more likely to go on to develop depression than the lowest-risk group, those who had neither high levels of cortisol nor depressive symptoms. Seventeen per cent of teens fell into this group but cortisol levels were not more useful than depression symptoms alone in pinpointing at-risk girls.
Although there may be a social stigma associated with those students who are identified as having a high risk of developing depression, the potential benefits could outweigh that. The necessary screening could be carried out confidentially and collected over a few days. The sooner students start to see a therapist may help with students' overall well being by giving them more support for the already difficult teenage years that are typically filled with emotional turmoil.
"It's better than leaving them alone in their bedrooms to get worse and worse," Sahakian says.
Although talking therapies such as cognitive behavioral therapy may not be the best treatment for boys who tend to be more visual, argues Sahakian, the screening would allow for targeted treatment and a better way to allocate resources.
At the moment the questionnaire and testing of cortisol is only beneficial to teenage boys although depression is more common among teenage girls and they are more likely to develop it. It is believed an equivalent test can be found with more research for girls as it is believed that girls may naturally have higher levels of cortisol than boys.
More research is also hoped to be more fruitful in finding other subtypes of depression identified by different biomarkers and therefore result in better treatments.