According to Christian Jarrett, they’re considerable:
Psychologists are recognizing the strengths of people who are prone to anxiety. For example, there’s research showing that people more prone to anxiety are quicker to detect threats and better at lie detection. Now Alexander Penney and his colleagues have conducted a survey of over 100 students and they report that a tendency to worry goes hand in hand with higher intelligence.
The researchers asked the students to complete measures of worry, anxiety, depression, rumination, social phobia, dwelling on past social events, mood, verbal intelligence, non-verbal intelligence, and test anxiety. This last measure was important because the researchers wanted to distinguish trait anxiety from in-the-moment state anxiety and how each relates to intelligence. The key finding was that after controlling for the influence of test anxiety and current mood, the students who reported a general habit of worrying more (e.g. they agreed with survey statements like “I am always worrying about something”) and/or ruminating more (e.g. they said they tended to think about their sadness, or think “what am doing to deserve this?”) also tended to score higher on the test of verbal intelligence, which was taken from the well-known Wechsler Adult Intelligence Scale.
The Dish 