Skip to main content

Ian Johnston trims medicinal marijuana plants at Tweed Inc. in Smith Falls, Ont., on Monday.LARS HAGBERG/AFP / Getty Images

A federal panel reporting to Ottawa on the next steps toward legalizing marijuana is expected to call for a comprehensive regime to monitor the impacts of bringing the substance out of the shadows and into the mainstream. And that could make Canada the world's first national case study on the dangers – and potential benefits – of cannabis when the drug becomes legal, some of the country's leading drug researchers say.

Researchers must study the dangers, such as impaired driving and more young people using it, says Dan Werb, director of the Toronto-based International Centre for Science in Drug Policy. But, he adds, they must also be open to looking for pot's potential public-health benefits, such as people substituting cannabis for alcohol or opioids.

"The one mistake government could make is focusing strictly on cannabis-related outcomes," Dr. Werb said. "Cannabis, by almost every measure, is a safer drug than alcohol, than cocaine, than heroin, than amphetamines and tobacco."

Read more: Better tracking of pot prescriptions sought by Canadian doctors' bodies

Read more: Marijuana task force submits report outlining framework for legal system

Read more: Globe Investigation: What's in your weed? We tested dispensary marijuana to find out

"The question for me isn't really about how many people use cannabis after we regulate it. The question is: How many people use [other drugs such as] alcohol?" he said in an interview in Vancouver.

"So, if we see increases in cannabis use, but we see a comparable reduction in alcohol use, to me, that is a massive public-health success. If we're only focused obsessively on cannabis, we're going to miss the broader picture here."

On Wednesday, Toronto's Centre for Mental Health and Addiction released data from its latest annual survey of Ontario that showed more than 14 per cent of adults used cannabis last year – that's up from 9 per cent reported in 1996. Of note, the organization said more people over the age of 50 in that province acknowledged using the substance last year (23 per cent) compared with a decade ago when only six per cent of respondents said they consumed marijuana.

Cannabis was deemed less dangerous than tobacco in a 2010 study that ranked 20 legal and illegal drugs based on the dependence, social and physical harms they caused. The report, published in the British medical journal The Lancet, ranked tobacco as more harmful than cannabis, while both were considered far less dangerous to users and the general public than heroin, cocaine and alcohol.

Uruguay is the only other country to have legalized the recreational sale and use of marijuana, but sales have been very slow to roll out and the tiny South American country has a population about a 10th the size of Canada.

Gathering baseline data on how Canadians are using medical and illegal cannabis right now also is seen as something the task force has identified as a priority.

Rebecca Jesseman, senior policy adviser at the government-funded Canadian Centre for Substance Abuse, has studied how Washington and Colorado rolled out recreational pot sales and said officials in both American states expressed regret that good data was not extensively collected before legalization.

"The task force and Health Canada very clearly recognize the need to be as proactive as possible in getting that research under way," said Ms. Jesseman, whose organization was criticized in a Health Canada review earlier this year for its reticence to embrace the harm-reduction approach to illicit substances.

Ottawa should continue to conduct larger countrywide surveys of alcohol, tobacco and drug use to gather information about cannabis, she said, while stakeholder groups should be funded to carry out more targeted studies on issues such as emergency-room visits linked to the drug as well as its impacts on respiratory and mental-health disorders.

M.J. Milloy, an infectious-disease epidemiologist who is studying the therapeutic effects of marijuana at the B.C. Centre for Excellence in HIV/AIDS, said he is about to start recruiting 1,000 clients of illegal Vancouver dispensaries for a study into how and why they use cannabis for medical and recreational purposes. He has funding for the initial round of interviews, but hopes to secure resources to once again ask these people about their habits after cannabis is legalized.

He said his study should shed light on how everyday Canadians are using the substance and will stand in contrast to previous studies, many of which were conducted in hospitals or jails involving "people who have been pathologized."

"By recruiting from dispensaries, we are trying to get a clearer, less-biased picture of the role cannabis plays in the health and wellness of Canadians," Dr. Milloy said.

Dr. Milloy and Dr. Werb, who both squared off against former prime minister Stephen Harper during the past election campaign over his claims about the harms of cannabis use, differ on which organization should oversee this effort to study legalization. Dr. Milloy said a research body affiliated with a university has the ability to depoliticize the data, while Dr. Werb said provincial organizations such as the Ontario Drug Policy Research Network might be best poised to analyze and disseminate information quickly and effectively.