CNN Chief Medical Correspondent Sanjay Gupta’s announcement last week that he now supports medical marijuana has sparked a debate among drug policy experts. He wrote an online piece, “Why I Changed My Mind on Weed,” which promoted his documentary, “Weed,” that ran on CNN Sunday night.

Marijuana “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 wrote.

Formerly, Gupta was a vocal opponent of legalizing marijuana. In 2009, he wrote a piece in Time entitled, “Why I Would Vote No on Pot.”

Nora Volkow, Director of the National Institute on Drug Abuse, told USA Today the debate around marijuana should not focus on whether it is less harmful than alcohol or nicotine, but what harm would be caused by legalizing another drug. “If you look at the data … the costs associated with drugs in our country, which are gigantic, are driven mostly by legal drugs because they’re so accessible. (The legalization of marijuana) will immediately increase the adverse affects,” she said.

Volkow noted marijuana is harmful to teens’ brain development. If the drug is legalized, they may have more access to it, and may consider it less harmful or dangerous. She adds the term “medical marijuana” is misleading, because the Food and Drug Administration has not assessed or approved the drug or its chemical contents, a requirement for all medicines used in the United States.

Jamison Monroe, founder and CEO of Newport Academy in California, a drug treatment program for adolescents, says Gupta’s support of medical marijuana, and the growing legalization movement, “definitely make the work we do more difficult. I don’t think you could say just because one drug is legal something else should be legal. If it does become legalized though, there should at least be an age limit.”