In a study in the Proceedings of the National
Academies of Science (PNAS) journal, the team found that teenage
boys who have a combination of depressive symptoms and raised levels
of the stress hormone cortisol are up to 14 times more likely to
develop major depression than those who show neither trait.
The findings suggest teenagers could in future be screened for such
signals, and those at highest risk could be helped to develop the
kind of coping strategies and "brain fitness" to help them avoid
"We're very bad about looking after our mental health, and yet the
problems of mental health are extremely common," said Barbara
Sahakian, a Cambridge University professor of clinical
neuropsychology who worked on the study.
"Depression is one of the greatest global burdens of disease — it's
a much bigger problem than heart disease or cancer and it's much
Depression affects around 350 million people worldwide and at its
worst can blight patients' lives for decades, affecting their
relationships, work and ability to function. It can also lead to
suicide, which alone leads to a million deaths a year.
"Depression is a terrible illness," said Ian Goodyer, a child and
adolescent psychiatrist who led the research team. "(And) we now
have a very real way of identifying those teenage boys most likely
to develop clinical depression."
He said armed with such knowledge, doctors and other carers 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".
According to the World Health Organization, prevention programs — including boosting cognitive, problem-solving and social skills in
children — have been shown to reduce depression, and earlier
intervention is more effective.
Different factors are thought to influence the development of
depression, including genetics, brain chemistry, lifestyle and
upbringing. Key triggers for the condition can include stressful
life events, medical illness and alcohol abuse.
For their study, Goodyer's team measured levels of cortisol in
saliva from two large separate 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.
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Using self-reports, collected over 12 months, of any symptoms of
depression — such as feeling sad or anxious — and combining them
with the cortisol results, the researchers then divided the
teenagers into four sub-groups ranging from those with normal levels
of cortisol and low symptoms of depression in Group 1 through to
those teenagers with more cortisol and high symptoms of depression
in Group 4.
Tracking the teenagers for three years, the team found that those in
Group 4 were on average seven times more likely than those in Group
1, and two to three times more likely than in the other two groups,
to develop clinical depression.
Further analysis showed that boys in Group 4 were 14 times more
likely to develop clinical depression than those in Group 1, and two
to four times more likely to develop it than either of the other two
Commenting on the findings, Oliver Howes at the Institute of
Psychiatry and the Maudsley Hospital at King's College London noted
that depression is "incredibly costly to society" and cited a 2011
European College of Neuropsychopharmacology report that said mood
disorders cost Europe alone more than 110 billion euros ($150 bln) a
"We desperately need ways to identify people at high risk of
depression early so we can potentially prevent its onset and treat
it early to reduce its burden. In this context, (this) study... is a
landmark in the field," he said.
(Editing by Jon Boyle)
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