You may support California’s Proposition 19, the Regulate, Control and Tax Cannabis Act of 2010, because you think the war on drugs unfairly targets minorities. You may be in favor of it because you think it’s up to you, not the government, to decide what substances you’d like to consume as long as you don’t harm others. Or you may be sympathetic to the ballot measure based on the testimonials of patients with cancer or AIDS who swear that medical marijuana helps them cope with their illness.

But if pot is made legal, what would that mean for public health in the Golden State? Nothing good, says Keith Humphreys, a professor of psychiatry and behavioral medicine at the Stanford School of Medicine.

Humphreys, a clinical psychologist who recently spent a year in the Obama administration’s Office of National Drug Control Policy as a senior policy advisor, says the health effects of Proposition 19 are being overlooked by the 52% of Californians who supported the measure in a recent poll. In a podcast available on the Stanford website, he says his No. 1 fear is that it would create a lucrative product line for tobacco companies or create an industry that would stand “shoulder to shoulder with them lobbying against every anti-smoking restriction and expansion of public health and every taxation initiative.”

Cigarettes still kill 400,000 people each year despite decades of regulation and anti-smoking campaigns, Humphreys said. But there’s reason to fear that Proposition 19 could make things worse. In European countries like the Netherlands, tobacco and marijuana are often smoked together and the combination is “both more addictive and more cancer-producing than either of those separately,” he said.

Humphreys said he has no doubt that marijuana has legitimate medical uses, and compounds within the plant will probably be turned into “maybe half a dozen decent medications” to alleviate pain, improve appetite and treat muscle spasms for patients with multiple sclerosis. But that doesn’t mean consumption of the entire plant -- which contains more than 200 chemicals -- is either beneficial or safe, especially when smoked, he said.

“Cocaine has medical uses,” especially as an anesthetic, Humphreys said, but that doesn’t mean it “should be available at 7-Eleven.”

You can download the complete podcast here.

-- Karen Kaplan

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