“The science is clear” on the dangers of marijuana, claims a new government ad campaign. But it’s a murky message because when it comes to the medicinal benefits of the drug, the same government also maintains there isn’t enough scientific study.

The controversial new anti-drug crusade aims to encourage parents to talk to teenagers about the effects of marijuana on their brains and how it “can damage a teen for life.”

In the Health Canada campaign — the same department charged with overseeing the country’s burgeoning medical marijuana industry — the government’s opposition to marijuana is unequivocal: “The science is clear. Marijuana use equals health risks.”

The problem is that while the government’s anti-marijuana position may be clear, the science behind its stance is anything but. Because marijuana is illegal, few randomized, controlled trials — the gold standard in the scientific community — have been conducted on its harms and benefits.

The commercial warns that marijuana can impair concentration and even cause hallucinations in some cases. The ad also suggests that marijuana is 300 to 400 per cent stronger than it was 30 years ago, but does not cite the origins of this information. Instead, it directs viewers to a government website for more information.

Health Canada also goes so far as to point out that marijuana is not an approved drug or medicine in Canada. The reason the government refuses to approve the drug? Not enough science.

The government says it cannot endorse the use of the drug because its effects have not been tested in clinical trials the way pharmaceuticals have.

The lack of clinical trials on the efficacy and side effects of marijuana has been a major sticking point for many doctors. They’re used to prescribing pharmaceuticals with dosages that have been determined by clinical studies.

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