Scientists speak out against false cannabis claims

published on August 12, 2015

Leading international scientific body reviews thirteen oft-repeated claims on cannabis use and regulation, finds that none are strongly supported by scientific evidence

Toronto, Canada (August 12, 2015) – Many scientists are increasingly frustrated by the disregard of scientific evidence on cannabis use and regulation. To set the record straight, the International Centre for Science in Drug Policy (ICSDP), a global network of scientists working on drug policy issues, released two groundbreaking reports today evaluating the strength of commonly heard cannabis claims.

“State of the Evidence: Cannabis Use and Regulation,” is a comprehensive overview of the scientific research on major claims made about cannabis. It is paired with a summary report, “Using Evidence to Talk About Cannabis,” which equips readers with evidence-based responses to the claims.

“We are at a critical juncture, as more and more jurisdictions are reconsidering their policies on cannabis,” said Dr. Dan Werb, Director of the ICSDP. “Yet, the public discourse around cannabis is filled with frequently repeated claims that are simply not supported by the scientific evidence.”

Dr. Werb explained: “Just yesterday, Stephen Harper stated that cannabis legalization “would only serve to make drugs more accessible to our children,’ a claim that is unsupported by the scientific evidence. In fact, we’ve seen sustained, high levels of cannabis availability among youth in Canada under our current policies. Given that policy decisions are influenced by public opinion and media reports, there is a serious danger that the repetition of false claims, especially by our country’s leaders, will lead to policies that further put our youth at risk.”

To investigate this issue, the ICSDP convened scientists to conduct a review of thirteen oft-repeated claims about cannabis use and regulation. The review found that none of the claims were strongly supported by the scientific evidence.

The majority of cannabis use claims outlined in the report tend to either misinterpret or overstate the existing scientific evidence. Dr. M-J Milloy, Research Scientist at the BC Centre for Excellence in HIV/AIDS, explained, “As is clear from the reports, there simply is not sufficient evidence to support many claims made about cannabis. For example, while it has been claimed that cannabis use can lead to lethal damage to the heart, the evidence is weak at best.” Dr. Milloy, who is investigating the protective effect of cannabis use on HIV disease progression, further noted that, “As a scientist researching medical cannabis, these unscientific claims have the unfortunate side effect of making it difficult – and sometimes impossible – to conduct research that has the potential to save people’s lives.”

Yet, other claims are even more far fetched. “Overstating the addictiveness and harms of cannabis ultimately has the potential to breed resentment and distrust of public institutions,” said Dr. Evan Wood, Canada Research Chair in Inner City Medicine at the University of British Columbia. “The evidence tells us that the vast majority of individuals who experiment with cannabis will experience no serious adverse effects and that legal psychoactive drugs like alcohol and tobacco are much more harmful and addictive.”

The review also found that many claims about cannabis regulation overlook an important fact: that regulation shifts control of cannabis markets from criminal entrepreneurs and into the hands of government. According to Dr. Wood, “The common claim that “regulation will increase the accessibility of cannabis’ is misleading. Youth already have free and easy access to cannabis under prohibition and the taxation and regulation of adult cannabis use would allow governments to set regulatory controls to reach policy goals. For example, the current wave of cannabis regulation occurring across the Americas has included strict legal age restrictions, and evidence does not suggest a significant increase in the use of cannabis among young people under these systems.”

The new reports are a resource for journalists, policymakers, and members of the general public who would like to engage with the complex issues surrounding global cannabis use and regulation. Scientists and academics will be holding an ongoing conversation on Twitter using the hashtag #CannabisClaims at the @icdsp handle starting on August 12, 2015. Interested parties can also sign up for the ICSDP newsletter to get updates on how supporters around the world are coming together to bring scientific evidence to the public discourse on cannabis.

Cannabis policy is a federal election issue in Canada, as the Liberal Party has stated that they will legalize and regulate cannabis markets if elected, while the New Democratic Party has supported decriminalizing cannabis use, and the Conservative Party is, in contrast, committed to a “tough on crime’ approach to drugs. Municipalities such as Vancouver have also forged ahead with the regulation of cannabis dispensaries in the absence of a coherent federal strategy. As the conversation progresses in Canada, these reports are intended to provide an evidence base for decisions on cannabis policy.