They were believed to make people mentally slow.

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Studies have shown that staying mentally and physically active can slow or even prevent Alzheimer's-related dementia.

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Much of her recent work at Stanford University has debunked stereotypes about how older people are uniformly slow, cranky and mentally impaired.

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When none of this turned out to be true, however--the shooter was not really a political actor at all, but just a mentally ill lost soul with no connection to partisan politics--the scare began a slow retreat.

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