White Coat, Black Art·The Dose

Cannabis use rose over the pandemic, so what do you need to know about the risks?

Whether we're smoking, vaping, eating, or even drinking it, we've used cannabis more over the course of the pandemic, recent data suggests. So what are the risks of cannabis use? And how can you minimize those risks? Neuroscientist Sarah Konefal, a research and policy analyst with Canadian Centre on Substance Use and Addiction, has the lowdown on the reducing the harms of getting high.

Stick to occasional use and low THC cannabis: expert

Smoking is still the most common way of ingesting cannabis, but edibles are gaining in popularity, according to Statistics Canada. (David Donnelly/CBC)

Whether we're smoking, vaping, eating, or even drinking it, we've used cannabis more over the course of the pandemic, recent data suggests.

By the end of 2020, nearly 6.2 million people aged 15 or older — or 20 per cent of Canadians in that age group — reported having used cannabis in the past three months, compared to 17.5 per cent in the first quarter of 2019, according to Statistics Canada. Daily or almost daily use also increased to 7.9 per cent from 6.1 per cent in 2019. (Canada legalized non-medical cannabis for adults in October 2018.) 

"Survey data shows that especially early on in the pandemic, the main reasons people were saying they were using cannabis more frequently were stress, boredom and loneliness," neuroscientist Sarah Konefal, a research and policy analyst with Canadian Centre on Substance Use and Addiction, told Dr. Brian Goldman, host of White Coat, Black Art and The Dose

A separate Statistics Canada survey, released in March, found that 34 per cent of Canadians said their cannabis consumption increased compared to pre-pandemic. 

Neuroscientist Sarah Konefal, a research and policy analyst with Canadian Centre on Substance Use and Addiction, says there are ways to reduce the risk of cannabis use. (Submitted by Sarah Konefal)

Additionally, cannabis retail sales in 2020 were $2.6 billion, more than double sales in 2019, the data found.

Statistics Canada noted that continued monitoring of cannabis use is necessary because the impact of the pandemic is difficult to measure — and the retail landscape is shifting quickly in different provinces, with more stores opening and more products coming to market. 

While the majority of people who use cannabis still smoke it, edibles are increasingly popular with 41 per cent of people reporting using them in 2020, about ten per cent more than in 2019. Approximately 23 per cent reported vaping cannabis, about a five per cent increase from 2019.

Any method of cannabis consumption carries risk, said Konefal, so Canadians who choose to use it should follow Canada's recommendations to reduce health-associated risks with cannabis.

According to these guidelines, cannabis can affect your thinking, physical coordination, and increase your risk of accidents and injuries, as well as lead to reproductive issues and mental health problems, including dependence and cannabis use disorder — but there are ways to reduce these harms, said Konefal.

Stick to occasional use, lower THC

One of the key ways to reduce harms from cannabis is by using it only occasionally, which she defines as "three or four times a month."

"There's really no evidence to show that occasional use … leads to any long-term impacts," said Konefal.

But the more often you smoke, the more risks there are — particularly for young people, aged 18 to 30, who have the highest risk for adverse outcomes from using cannabis regularly, according to Konefal.

A customer sniffs a display sample of marijuana, in a tamper-proof container secured with a cable, sold at Evergreen Cannabis, a marijuana retail shop, in Vancouver. (The Associated Press/Elaine Thompson)

"One of the recommendations is, if possible, delaying the initiation of cannabis use beyond the ages of 16 or 17. [That's] been shown to be really beneficial in reducing risks for poor mental health outcomes in particular, but as well as physical health outcomes."

Konefal also said to choose cannabis with lower levels of THC (tetrahydrocannabinol), the substance that makes you feel high, because THC is the main molecule linked to certain harms, especially adverse mental health outcomes.

Health Canada regulates the amount of THC in legal cannabis products, which Konefal said, is a critical reason to make sure you buy from legal sources. 

Vaping vs. smoking 

The evidence is pretty conclusive that smoking marijuana is not great for the lungs and is associated with chronic bronchitis, according to James MacKillop, the director of the Michael G. DeGroote Centre for Medicinal Cannabis Research, at McMaster University and St. Joseph's Healthcare in Hamilton, Ont.

"Vaping seems like a healthier alternative insofar as you're getting rid of a lot of the dried plant material that's in cannabis smoke," said MacKillop, who is also the director of the Peter Boris Centre for Addictions Research.

A disposable vape is displayed at the Ontario Cannabis Store in Toronto. (THE CANADIAN PRESS/Tijana Martin)

That being said, there isn't a large body of scientific literature studying vaping versus smoking of cannabis products to quantify any reduction in harms, he added.

While MacKillop acknowledged concerns around severe lung illness associated with vaping, he noted this illness seemed to result from using illicit products with dangerous additives. Another reason, he said, to stick to legal, regulated sources. 

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Konefal's advice with edibles — cannabis oil added to food like a gummy candy — is to "start low and go slow."

While Health Canada allows edibles to be sold with up to 10 mg of THC per unit, Konefal suggests starting with 2.5 mg, and then waiting because of a delayed onset of the high with edibles.

The risk is that you may feel nothing initially and consume more, which could lead to an overdose and needing a trip to the ER, she said.

Edibles are increasingly popular, with 41 per cent of Canadians who reported using cannabis in 2020 saying they've eaten it in some form. (Victor Moussa/Shutterstock)

A Canadian Medical Association Journal article last year on the health risks of cannabis edibles pointed to the findings of a 2019 U.S. study reviewing nearly 10,000 ER visits from January 2012 to December 2016 at a Colorado hospital. Even though cannabis smoking-related ER visits were more frequent, cannabis edible users were more likely to have visits for acute psychiatric conditions, such as psychosis and anxiety.

Cannabis use disorder 

It's important to know you can get addicted to cannabis, said Konefal, and cannabis use disorder, while uncommon, is one of the biggest risks associated with marijuana use.

She's worried there could be a spike in cannabis use disorder during the pandemic because young people, aged 18 to 20, are the most likely to report an increase in use in the past year and the cohort that's most at risk for cannabis addiction.

Konefal said signs of cannabis use disorder include using more cannabis than intended, trying unsuccessfully to control use, failing to fulfil major obligations at work, home or school because of cannabis, or using in dangerous situations, like driving.

A woman walks past a pot shop in Nelson, B.C. (Bob Keating/CBC)


While some marijuana fans extol the virtues and benefits of cannabis use, MacKillop emphasized there are no known health benefits to cannabis. 

"No one should think of TCH as a vitamin," he said. 

"But the reality is for people who use occasionally, for people who are not using risky levels or have cannabis use disorder, there may be certainly other psychological benefits in terms of the pleasures that are associated with the drug."