"There are 40 million people in America alone who have excessive sleepiness as their major symptom, and that's who we're after, " he says.

FORBES: Magazine Article

Excessive grooming can be a symptom of obsessive-compulsive disorder, aggression and violence can indicate anxiety, and a refusal to eat can suggest depression in an animal.

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Most excessive game playing is usually a symptom of an underlying problem.

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The fourth symptom of overheating, and one of the most important, is excessive credit expansion, which can lead to asset bubbles as well as inflation.

ECONOMIST: Economics focus