Dr. Sanjay Gupta, the neurosurgeon and chief medical correspondent at CNN, has changed his mind about medical marijuana. 

"I mistakenly believed the Drug Enforcement Agency listed marijuana as a schedule 1 substance because of sound scientific proof," Gupta writes in an apologetic column on CNN. As it turns out, "they didn't have the science to support that claim," Gupta concludes. "It doesn't have a high potential for abuse, and there are very legitimate medical applications."

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