Addictions
Four new studies show link between heavy cannabis use, serious health risks
Cannabis products purchased in Ontario and B.C., including gummies, pre-rolled joints, chocolates and dried flower; April 11, 2025. [Photo credit: Alexandra Keeler]
By Alexandra Keeler
New Canadian research shows a connection between heavy cannabis use and dementia, heart attacks, schizophrenia and even death
Six months ago, doctors in Boston began noticing a concerning trend: young patients were showing up in emergency rooms with atypical symptoms and being diagnosed with heart attacks.
“The link between them was that they were heavy cannabis users,” Dr. Ahmed Mahmoud, a cardiovascular researcher and physician in Boston, told Canadian Affairs in an interview.
These frontline observations mirror emerging evidence by Canadian researchers showing heavy cannabis use is associated with significant adverse health impacts, including heart attacks, schizophrenia and dementia.
Sources warn public health measures are not keeping pace with rapid changes to cannabis products as the market is commercialized.
“The irony of this moment is that society’s risk perception of cannabis is at an all-time low, at the exact moment that the substance is probably having increasingly negative health impacts,” said Dr. Daniel Myran, a physician and Canada Research Chair at the University of Ottawa. Myran was lead researcher on three new Canadian studies on cannabis’ negative health impacts.
Legalization
Canada was the first G7 country to create a commercial cannabis market when it legalized the production and sale of cannabis in 2018.
The drug is now widely used in Canada.
In the 2024 Canadian Cannabis Survey, an annual government survey of cannabis trends, 26 per cent of respondents said they used cannabis for non-medical purposes in the past year, up from 22 per cent in 2018. Among youth, that number was 41 per cent.
Health Canada’s website warns that cannabis use can lower blood pressure and raise heart rates, which can increase the risk of a heart attack. But the warnings on cannabis product labels vary. Some mention risks of anxiety or effects on memory and concentration, but make no mention of cardiovascular risks.
The annual cannabis survey also shows a significant percentage of Canadians remain unaware of cannabis’ health risks.
In the survey, only 70 per cent of respondents said they had enough reliable information to make informed decisions about cannabis use. And 50 per cent of respondents said they had not seen any education campaigns or public health messages about cannabis.
At the same time, researchers are finding mounting evidence that cannabis use is associated with health risks.
A 2023 study by researchers at the University of Calgary, the University of Alberta and Alberta Health Services found that adults with cannabis use disorder faced a 60 per cent higher risk of experiencing adverse cardiovascular events — including heart attacks. Cannabis use disorder is marked by the inability to stop using cannabis despite negative consequences, such as work, social, legal or health issues.
Between February and April of this year, three other Canadian studies linked frequent cannabis use to elevated risks of developing schizophrenia, dementia and mortality. These studies were primarily conducted by researchers at the Ottawa Hospital Research Institute and ICES uOttawa (formerly the Institute for Clinical Evaluative Sciences).
“These results suggest that individuals who require hospital-based care for a [cannabis use disorder] may be at increased risk of premature death,” said the study linking cannabis-related hospital visits with increased mortality rates.
The three 2024 studies all examined the impacts of severe cannabis use, suggesting more moderate users may face lower risks. The researchers also cautioned that their research shows a correlation between heavy cannabis use and adverse health effects, but does not establish causality.
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Budtenders
Health experts say they are troubled by the widespread perception that cannabis is entirely benign.
“It has some benefits, it has some side effects,” said Mahmoud, the Boston cardiovascular researcher. “We need to raise awareness about the side effects as well as the benefits.”
Some also expressed concern that the commercialization of cannabis products in Canada has created a race to produce products with elevated levels of THC, the main psychoactive compound that produces a “high.”
THC levels have more than doubled since legalization, yet even products with high THC levels are marketed as harmless.
“The products that are on the market are evolving in ways that are concerning,” Myran said. “Higher THC products are associated with considerably more risk.”
Myran views cannabis decriminalization as a public health success, because it keeps young people out of the criminal justice system and reduces inequities faced by Indigenous and racialized groups.
“[But] I do not think that you need to create a commercial cannabis market or industry in order to achieve those public health benefits,” he said.
Since decriminalization, the provinces have taken different approaches to regulating cannabis. But even in provinces where governments control cannabis distribution, such as New Brunswick and Nova Scotia, products with high THC levels dominate retail shelves and online storefronts.
In Myran’s view, federal and provincial governments should instead be focused on curbing harmful use patterns, rather than promoting cannabis sales.
Ian Culbert, executive director of the Canadian Public Health Association, thinks governments’ financial interest in the cannabis industry creates a conflict of interest.
“[As with] all regulated substances, governments are addicted to the revenue they create,” he said. “But they also have a responsibility to safeguard the well-being of citizens.”
Culbert believes cannabis retailers should be required to educate customers about health risks — just as bartenders are required to undergo Smart Serve training and lottery corporations are required to mitigate risks of gambling addiction.
“Give ‘budtenders’ the training around potential health risks,” he said.
“While cannabis may not be the cause of some of these negative health events … it is the intersection at which an intervention can take place through the transaction of sales. So is there something we can do there that can change the trajectory of a person’s life?”
This article was produced through the Breaking Needles Fellowship Program, which provided a grant to Canadian Affairs, a digital media outlet, to fund journalism exploring addiction and crime in Canada. Articles produced through the Fellowship are co-published by Break The Needle and Canadian Affairs.
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News release from Alberta RCMP
Virtual Opioid Dependency Program serves vulnerable population in Red Deer
Since April 2024, your Alberta RCMP’s Community Safety and Well-being Branch (CSWB) has been piloting the Virtual Opioid Dependency Program (VODP) program in Red Deer to assist those facing opioid dependency with initial-stage intervention services. VODP is a collaboration with the Government of Alberta, Recovery Alberta, and the Alberta RCMP, and was created to help address opioid addiction across the province.
Red Deer’s VODP consists of two teams, each consisting of a police officer and a paramedic. These teams cover the communities of Red Deer, Innisfail, Blackfalds and Sylvan Lake. The goal of the program is to have frontline points of contact that can assist opioid users by getting them access to treatment, counselling, and life-saving medication.
The Alberta RCMP’s role in VODP:
- Conducting outreach in the community, on foot, by vehicle, and even UTV, and interacting with vulnerable persons and talking with them about treatment options and making VODP referrals.
- Attending calls for service in which opioid use may be a factor, such as drug poisonings, open drug use in public, social diversion calls, etc.
- Administering medication such as Suboxone and Sublocade to opioid users who are arrested and lodged in RCMP cells and voluntarily wish to participate in VODP; these medications help with withdrawal symptoms and are the primary method for treating opioid addiction. Individuals may be provided ongoing treatment while in police custody or incarceration.
- Collaborating with agencies in the treatment and addiction space to work together on client care. Red Deer’s VODP chairs a quarterly Vulnerable Populations Working Group meeting consisting of a number of local stakeholders who come together to address both client and community needs.
While accountability for criminal actions is necessary, the Alberta RCMP recognizes that opioid addiction is part of larger social and health issues that require long-term supports. Often people facing addictions are among offenders who land in a cycle of criminality. As first responders, our officers are frequently in contact with these individuals. We are ideally placed to help connect those individuals with the VODP. The Alberta RCMP helps those individuals who wish to participate in the VODP by ensuring that they have access to necessary resources and receive the medical care they need, even while they are in police custody.
Since its start, the Red Deer program has made nearly 2,500 referrals and touchpoints with individuals, discussing VODP participation and treatment options. Some successes of the program include:
- In October 2024, Red Deer VODP assessed a 35-year-old male who was arrested and in police custody. The individual was put in contact with medical care and was prescribed and administered Suboxone. The team members did not have any contact with the male again until April 2025 when the individual visited the detachment to thank the team for treating him with care and dignity while in cells, and for getting him access to treatment. The individual stated he had been sober since, saying the treatment saved his life.
- In May 2025, the VODP team worked with a 14-year-old female who was arrested on warrants and lodged in RCMP cells. She had run away from home and was located downtown using opioids. The team spoke to the girl about treatment, was referred to VODP, and was administered Sublocade to treat her addiction. During follow-up, the team received positive feedback from both the family and the attending care providers.
The VODP provides same-day medication starts, opioid treatment transition services, and ongoing opioid dependency care to people anywhere in Alberta who are living with opioid addiction. Visit vodp.ca to learn more.
“This collaboration between Alberta’s Government, Recovery Alberta and the RCMP is a powerful example of how partnerships between health and public safety can change lives. The Virtual Opioid Dependency Program can be the first step in a person’s journey to recovery,” says Alberta’s Minister of Mental Health and Addiction Rick Wilson. “By connecting people to treatment when and where they need it most, we are helping build more paths to recovery and to a healthier Alberta.”
“Part of the Alberta RCMP’s CSWB mandate is the enhancement of public safety through community partnerships,” says Supt. Holly Glassford, Detachment Commander of Red Deer RCMP. “Through VODP, we are committed to building upon community partnerships with social and health agencies, so that we can increase accessibility to supports in our city and reduce crime in Red Deer. Together we are creating a stronger, safer Alberta.”
By Alexandra Keeler
Across Canada, mobile health models are increasingly being used to offer care to rural and underserved communities
Saskatchewan has launched a small fleet of mobile wellness buses to improve access to primary health care, mental health and addiction services in the province.
The first bus began operating in Regina on Feb. 12. Another followed in Prince Albert on March 21. Saskatoon’s bus was unveiled publicly on April 9. All three are former coach buses that have been retrofitted to provide health care to communities facing barriers to access.
“Mobile health units are proven to improve outcomes for people facing barriers to healthcare,” Kayla DeMong, the executive director of addiction treatment centre Prairie Harm Reduction, told Canadian Affairs in an email.
“We fully support this innovative approach and are excited to work alongside the health bus teams to ensure the people we support receive the care they need, when and where they need it.”
Wellness buses
Like all provinces, Saskatchewan has been grappling with the opioid crisis.
In 2023, an estimated 457 individuals died from overdoses in the province. In 2024, that number fell to 346. But the province continues to struggle with fatal and non-fatal overdoses.
In late February, Saskatoon firefighters responded to more than 25 overdoses in a single 24-hour period. Just over a week later, they responded to 37 overdoses within another 24-hour window.
Saskatchewan’s wellness buses are part of the province’s plan to address these problems. In April 2025, the province announced $2.4 million to purchase and retrofit three coach buses, plus $1.5 million in annual operating funds.
The buses operate on fixed schedules at designated locations around each city. Each bus is staffed with a nurse practitioner, nurse and assessor coordinator who offer services such as overdose reversal kits, addiction medicine and mental health referrals.
“By bringing services directly to where people are, the health buses foster safer, more welcoming spaces and help build trusting relationships between community members and care providers,” said DeMong, executive director of Prairie Harm Reduction.
Saskatoon-based Prairie Harm Reduction is one of the local organizations that partners with the buses to provide additional support services. Prairie Harm Reduction provides a range of family, youth and community supports, and also houses the province’s only fixed supervised consumption site.
The mobile model
Saskatchewan is not the only province using wellness buses. Across Canada, mobile health models are increasingly being used to expand access to care in rural and underserved communities.
In Kingston, Ont., the Street Health Centre operates a retrofitted RV called PORCH (Portable Outreach Care Hub) that serves individuals struggling with homelessness and addiction.
“Our outreach services are extremely popular with our clients and community partners,” Donna Glasspoole, manager at Street Health Centre, said in an emailed statement.
“PORCH hits the road two to three days/week and offers a variety of services, which are dependent on the health care providers and community partners aboard.”
Street Health Centre also has a shuttle service that picks up clients in shelters and brings them to medical clinics or addiction medicine clinics.
The PORCH vehicles are not supported by provincial funding, but instead rely on support from the United Way and other grants. Glasspoole says the centre’s permanent location — which does receive government funding — is more cost-effective to operate.
“The vehicles are expensive to operate and our RV is not great in winter months and requires indoor parking,” she said.
Politically palatable
Many mobile health models currently do not provide controversial services such as supervised drug consumption.
The Saskatchewan Health Authority told Canadian Affairs the province’s new wellness buses will not offer supervised consumption services or safer supply, where drug users are given prescribed opioids as an alternative to toxic street drugs.
“There are no plans to provide supervised consumption services from the wellness buses,” Saskatchewan Health Authority spokesperson Courtney Markewich told Canadian Affairs in a phone call.
This limited scope may make mobile services more politically palatable in provinces that have resisted harm reduction measures.
In Ontario, some harm reduction programs have shifted to mobile models following Premier Doug Ford’s decision to suspend supervised consumption services located within 200 metres of schools and daycares.
In April, Toronto Public Health ended operations at its Victoria Street fixed consumption site, replacing it with street outreach and mobile vans.
The Ontario government’s decision to close the sites is part of a broader pivot away from harm reduction. The province is investing $378 million to transition suspended sites into 19 new “HART Hubs” that offer primary care, mental health, addictions treatment and other supports.
Glasspoole says that what matters most is not whether services are provided at fixed or mobile locations, but how care is delivered.
Models that “reduce barriers to care, [are] non-judgemental, and [are staffed by] trauma-informed providers” are what lead more people toward treatment and recovery, she said in her email.
In Saskatchewan, DeMong hopes the province’s new wellness buses help address persistent service gaps and build trust with underserved communities.
“This initiative is a vital step toward filling long-standing gaps in the continuum of care by providing low-barrier, community-based access to health-care services,” she said.
This article was produced through the Breaking Needles Fellowship Program, which provided a grant to Canadian Affairs, a digital media outlet, to fund journalism exploring addiction and crime in Canada. Articles produced through the Fellowship are co-published by Break The Needle and Canadian Affairs.
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