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Franco Vaccarino is president of the University of Guelph.

Ottawa’s plans for taxing legal cannabis have made headlines since the release of the 2018 federal budget. Less noticed, but no less important, was the news that the federal government will also invest in public education about the risks of cannabis use.

Canada is preparing to pass legislation allowing consumers to buy recreational cannabis. That’s a reasonable initiative. But we need to do it right.

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We need to be sure we understand the complexities and nuances of increased cannabis use in order to protect youth and people with mental health disorders and to implement programs that mitigate potentially harmful effects.

That’s especially true in Canada. Rates of cannabis use in this country are among the highest in the world. A 2013 study found that one in four Canadian youth had used cannabis that year, and as much as 28 per cent of 11- to 15-year-olds reported using it – the highest rate among developed countries.

Cannabis use usually begins in adolescence – just when most psychiatric disorders start to show up. Evidence from the United States shows that cannabis legalization may increase youth access; for instance, in Washington State, its use after legalization rose among students in Grades 8 and 10.

In the wider population, cannabis use is associated with lower motivation, problematic use of other substances and poorer psychiatric outcomes for people with psychosis and mood and anxiety disorders.

Rates of cannabis use disorder (CUD) are 2 to 3 per cent and may be rising. And studies suggest that people with mental health and addictive disorders have higher rates of cannabis use and CUD than the general population.

When it comes to cannabis legalization and psychiatric disorders, it’s caveat “hemp-tor,” part of the title of a paper in the Canadian Journal of Psychiatry that I’ve co-written with Dr. Tony George at the Centre for Addiction and Mental Health in Toronto and Dr. Kevin Hill at Harvard Medical School.

Our paper lays out a six-point plan intended to help protect vulnerable populations under Canada’s new legislative framework and to spark a conversation about improving mental health literacy in this country.

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First, Ottawa should create a national strategy for public education about the pros and cons of legalizing recreational cannabis. We need to ensure an open, sensible conversation based on the available evidence.

Second, the national working group on cannabis legalization has already called for accurate product labelling. But we need to go further, with public and physician education about the risks of products with high THC (the addictive component of cannabis) for youth and people with mental-health conditions.

Third, doctors, scientists and policy-makers should regularly review longitudinal health outcomes after legalization to guide changes to the legal age limit for the recreational use of cannabis.

Fourth, Canada needs a national surveillance system to monitor health outcomes and cannabis use before and after legalization.

Fifth, we must invest in treatment and capacity to address problematic cannabis use, perhaps funded by taxes on sales of recreational cannabis and mandatory corporate contributions.

Finally, medical students and doctors should receive training in the science of cannabis and its potential therapeutic effects to provide evidence-based advice and care for patients wishing to use recreational and medicinal cannabis.

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The federal government has already invested in public education and awareness activities in drug-impaired driving and health risks. It’s heartening to see that, in its 2018 budget, Ottawa has committed a total of $82.5-million over five years for public education and for studies of the impact of cannabis use on mental health.

Postsecondary institutions can also use their teaching and research strengths to lead in providing information and informing decisions on aspects of cannabis legalization.

Some of that work is already happening at the University of Guelph, where our expertise in agriculture and food includes a wide range of topics, from cannabis use for human and animal health to cannabis breeding and genetics, production, storage and processing.

Beyond universities, we need to involve other educators and scientists, consumers, policy-makers and governments in learning and sharing information about the risks of cannabis use, especially for the most vulnerable among us.

Legal cannabis is coming. Improved mental health literacy should come with it.

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