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Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge during the match between Andy Murray of Great Britain and Nicolas Almagro of Spain in the Quarterfinal of Men's Singles Tennis on Day 6 of the London 2012 Olympic Games at Wimbledon on August 2, 2012 in London, England.

As the election nears, a few candidates in close races might bite their nails. If they do, they could officially be diagnosed with a psychiatric disorder.

That's because the updated bible of psychiatry, "The Diagnostic and Statistical Manual of Mental Disorders," includes a new category called "The obsessive compulsive spectrum," which includes OCD and more common behaviors like nail biting.

Amy Standen reports.