Experts refute Harper’s claim pot is more dangerous than tobacco

published on October 6, 2015 by Mike Hager in The Globe and Mail

Is cannabis, as Conservative Party Leader Stephen Harper claims, “infinitely worse” than tobacco, a substance that kills tens of thousands of Canadians each year?

Definitely not, say medical researchers and addiction experts, who are refuting Mr. Harper’s provocative comparison between cigarettes and marijuana.

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Dan Werb, director of the Toronto-based International Centre for Science in Drug Policy, said research also shows there is a “massive disparity” between how easy it is to get addicted to each substance. Studies show 68 per cent of smokers become addicted over their lifetime, while about 10 per cent become dependent on cannabis, he said.

“If we are prohibiting drugs based on their addictive potential, then tobacco would be the first to be prohibited as it, by some estimates, has a greater addictive potential than heroin,” he said.

Dr. Werb said evidence that showed marijuana damages lungs or the heart is “highly equivocal,” whereas tobacco has been proven to be very damaging.

M.J. Milloy, an infectious-disease epidemiologist who is studying the therapeutic effects of marijuana at the BC Centre for Excellence in HIV/AIDS, also rebuked Mr. Harper for his claim that there are “overwhelming and growing scientific and medical evidence about the bad long-term effects of marijuana.”

Dr. Milloy said there are obvious short-term risks, such as driving when using cannabis, but there is no evidence that moderate, long-term pot use incurs substantial health costs.

Some research has linked teens’ long-term use of pot heavy with the psychoactive THC compound to mental-health issues such as psychosis and schizophrenia. But Dr. Milloy said no causal link has been proven and these young people might be genetically predisposed to such mental-health issues.