Sanjay Gupta

CNN medical correspondent Dr. Sanjay Gupta is reversing his position on medical marijuana and now endorses its use in a new essay and upcoming documentary.

"We have been terribly and systematically misled for nearly 70 years in the United States, and I apologize for my own role in that," Gupta, who penned an article for Time in 2009 titled "Why I Would Vote No on Pot," writes for CNN.com. "I didn't look hard enough, until now. I didn't look far enough. ... I was too dismissive of the loud chorus of legitimate patients whose symptoms improved on cannabis.

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For his film, titled simply Weed, Gupta writes that he spoke to "medical leaders, experts, growers and patients" around the world. In a departure from the DEA's view on marijuana, Gupta now believes that "it doesn't have a high potential for abuse, and there are very legitimate medical applications. In fact, sometimes marijuana is the only thing that works." He cites research estimating that 9 to 10 percent of adult marijuana users become dependent, as compared to 20 percent of cocaine users, 25 percent of heroin users and 30 percent of tobacco users.

However, Gupta adds, "developing brains are likely more susceptible to harm from marijuana than adult brains," and that regular marijuana use in teenagers could lead to a "permanent decrease in IQ" or "possible heightened risk of developing psychosis."

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"Much in the same way I wouldn't let my own children drink alcohol, I wouldn't permit marijuana until they are adults," he writes. "If they are adamant about trying marijuana, I will urge them to wait until they're in their mid-20s when their brains are fully developed."

Gupta specifically endorses the use of marijuana to treat cancer, neuropathic pain and post-traumatic stress disorder. "It is irresponsible not to provide the best care we can as a medical community, care that could involve marijuana," Gupta writes.

What do you think of Gupta's new position?