Melissa Dahl for Science of Us: 

The tendency to worry about stuff could be a sign of a certain kind of intelligence, according to a  paper in an upcoming edition of the journal  Personality and Individual Differences (hat tip to Christian Jarrett at the British Psychology Society's  Research Digest for spotting it first). A team led by Alexander Penney of Ontario's Lakehead University gave 126 undergrads a litany of surveys and questionnaires designed to measure both their intelligence and how much they tended to stress about events in their lives. (For instance, they were asked how strongly they agreed with statements like, "I am always worried about something.") After analyzing the results, Penney and his team found a correlation between worrying and verbal intelligence.