Suffering stress? You may have been born anxious

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Telling someone of a nervous disposition to calm down is a waste of time, according to scientists who have found that a nervous disposition may be something people are born with.

Researchers at the University of Wisconsin discovered that the brains of rhesus monkeys which suffered from an anxious disposition are wired differently, and thus, they suffer stress regardless of their circumstances.

The monkeys, which were studied because their brains are the closest match to those of adolescent humans, were monitored in three situations: while they were secure at home with their cage-mates, while they were alone and while they were exposed to an unfamiliar human carer.

The most anxious animals had increased activity within one part of their brain – the amygdala, which deals with fear and aggression – even when in a non-stressful environment.

When tested again 18 months later, the now adult monkeys which were found to be anxious had maintained their nervous traits.

The scientists say their findings could have implications for the treatment of mental illness.

"Prior to this research, we didn't know that you could detect a tendency towards anxiety so early in life, or that this level would remain so constant," said Dr Ned Kalin, who led the study, which is published in the onlinejournal Public Library of Science.

The findings refute the idea that severely shy or anxious children will just "grow out of it" and suggests that there should be a therapeutic intervention at a young age. "Looking at a way to settle down that part of the brain could be a major factor in reducing anxiety for many people," said Dr Kalin.