Heavy Marijuana Use Doesn't Damage Brain

Heavy Marijuana Use Doesn't Damage Brain

By Sid Kirchheimer
WebMD Medical News

July 1, 2003 -- Long-term and even daily marijuana use doesn't appear to cause permanent brain damage, adding to evidence that it can be a safe and effective treatment for a wide range of diseases, say researchers.

The researchers found only a "very small" impairment in memory and learning among long-term marijuana users. Otherwise, scores on thinking tests were similar to those who don't smoke marijuana, according to a new analysis of 15 previous studies.
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"We were somewhat surprised by our finding, especially since there's been a controversy for some years on whether long-term cannabis use causes brain damage," says lead researcher and psychiatrist Igor Grant, MD.

"I suppose we expected to see some differences in people who were heavy users, but in fact the differences were very minimal."