A new study has discovered a cognitive biomarker in teens that could identify those who are at high risk for future depression and anxiety. The marker may appear prior to the symptoms of depression and anxiety, and researchers believe a test for the biomarker could be used as an inexpensive way to screen adolescents for common emotional mental illnesses.

The study, published this week in the journal PLOS ONE, looked at 15 to 18 year olds who underwent genetic testing and environmental assessment. The were then given a computer test to gauge how they process emotional information. The test used words such as “joyful” and “failure” and had participants rate them as positive, negative, or neutral.

“Whether we succumb to anxiety and depression depends in part on our tendencies to think well or poorly of ourselves at troubled times,” said Dr. Ian Goodyer, co-author of the study and professor at the University of Cambridge. “How it comes about that some people see the ‘glass half full’ and think positively whereas other see the ‘glass half empty’ and think negatively about themselves at times of stress is not known.”

Study participants with a variation of a specific gene, exposure to intermittent family arguments for longer than six months, and violence between their parents before the age of six had more difficulty evaluating the emotion within words in the computer test. The researchers point to previous research, which associates a “maladjusted perception and response to emotions” with an increased risk of depression and anxiety.

“The evidence is that both our genes and our early childhood experiences contribute to such personal thinking styles,” said Goodyer. “Before there are any clinical symptoms of depression or anxiety, this test reveals a deficient ability to efficiently and effectively perceive emotion processes in some teenagers – a biomarker for low resilience which may lead to mental illnesses.”

The researchers hope the study could lead to an inexpensive cognitive test to screen for emotional mental illness in high school students who are at genetic risk for the illnesses.

“Having difficulty in processing emotions is likely to contribute to misunderstanding other people’s intentions and can make individuals emotionally vulnerable,” said Dr. Matthew Owens, lead author of the study and a researcher at the University of Cambridge. “This research opens up the possibility of identifying individuals at greatest risk and helping them with techniques to process emotions more easily or training them to respond more adaptively to negative feedback.”