Study shows cannabis use leads to less alcohol. Are we just swapping vices?

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Back before cannabis became legal in Canada in 2017, there was discussion about how it was going to mix with alcohol, writes Christine Sismondo in The Star. It turns out to have been much ado about nothing – research has linked people who use medical cannabis with less use of alcohol.

Some predicted legalisation would usher in a new age of weed-tinis, which prompted others to warn that the combination of the two would lead to new levels of reefer madness. Then, federal law essentially stopped that conversation the following year with its announcement that products containing alcohol and cannabis would be a no-go.

Now, a study suggests we probably didn’t have anything to worry about in the first place. Early results suggest the use of medical cannabis is associated with people drinking less alcohol, not more, continues Sismondo in the article published on 2 November 2020.

The Canadian Cannabis Patient Survey of 2019 – a national, cross-sectional study sponsored by a pharmaceutical and cannabis company named Tilray – has recently been released and the authors of a new paper in the International Journal of Drug Policy crunching the numbers say the results are striking and have wide-reaching implications.

Nearly half – 44% – of the patients who reported drinking alcohol before they started using medical cannabis said they were drinking less after starting.

A safer substitute

Keeping in mind that making an association isn’t the same as proving that taking medical cannabis causes people to drink less, if it turns out to be the case, it would sure be an interesting plot twist.

“For years, it was believed that cannabis and alcohol were complements and that people co-used these substances, because a lot of the time when we examined problematic use patterns, these two would go together,” says Philippe Lucas, a PhD candidate at the University of Victoria and vice-president of global patient research and access at Tilray.

Lucas, along with colleagues Susan Boyd, M-J Milloy and Zach Walsh, is also the author of the new paper, “Reductions in alcohol use following medical cannabis initiation: Results from a large cross-sectional survey of medical cannabis patients in Canada,” that analyses the survey’s results.

“But, more and more, as we put the pieces together, we’re seeing that cannabis products can be used as safer substitutes instead,” Lucas continues.

“We have a lot more evidence now to suggest that, for example, people use less alcohol on the days when they also use cannabis. And, on the evenings when they are using cannabis and going out with friends, they’re less likely to binge drink.”

Swapping one vice for another?

If people are just getting high in a different way, does it matter? Are people just swapping one vice for another?

On an intuitive level, some might think we’re borrowing trouble by trying to fix one drug problem with a new and different drug. And they’d be right to have serious qualms, if it weren’t for the fact that one drug carries way more health risks than the other.

“I don’t have the national data right in front of me, but the number of deaths estimated for a recent year in Canada would be about 1,100 for cannabis and about 18,000 for alcohol,” says Tim Stockwell, professor in the department of psychology and scientist at the Canadian Institute for Substance Use Research at the University of Victoria.

Although we don’t have firm numbers, per capita, more Canadians almost certainly use alcohol than cannabis, so that accounts for some of the difference between the numbers.

But Stockwell estimates alcohol consumption is likely more along the lines of two to three times as much as cannabis, which couldn’t account for the mortality rate being over 15 times higher for alcohol. (Nobody has done a dose-per-dose comparison to date and sales numbers are hard to pin down, since cannabis is still widely sold under the table.)

Harm reduction hope

The hope is, then, that cannabis could play a role in a harm reduction programme for people with alcohol dependence issues.

“You know, we’ve looked at harm reduction options for people using heroin but, when it comes to alcohol, there’s not much typically being done,” says Stockwell. “None of this is to say that cannabis is entirely safe and harmless. It isn’t.

“There’s a risk for lung disease and there’s road safety issues, but we’d be trading it for something that harms every organ in the body and probably has two or three hundred different diagnostic categories of disease that can be serious or fatal, compared with cannabis, which maybe has four or five.”

Prior to COVID-19, Stockwell was working with University of Victoria colleague Dr Bernie Pauly to design a study that would test the effectiveness of cannabis beverages as substitutes for alcohol in managed alcohol programmes – maintenance programmes for people with serious dependence issues.

Unfortunately, the pandemic meant it had to be postponed, but Stockwell says that the consultations he had with patients and caregivers convinced him there was a tremendous appetite for exploring alternatives to alcohol in the treatment setting.

Tilray’s Philippe Lucas says that harm reduction shouldn’t only be considered for people with diagnosed dependence issues. He argues that reducing alcohol by even a small percentage could lead to significant improvements in public health, based on numbers that correlate reduced road fatalities and mortality rates in Colorado, which opted to legalise recreational cannabis.

And, if it can help people better manage their alcohol consumption, it might also help people with opioid and tobacco dependency, a theory that scientists are currently working on.

“You know, for the longest time, we thought cannabis might be a gateway drug to more problematic substance use,” says Lucas. “And, more and more, there is a growing body of research that suggests that, rather than being a gateway drug, for some individuals with problematic substance use, cannabis can actually be an exit drug.”


Reductions in alcohol use following medical cannabis initiation: results from a large cross-sectional survey of medical cannabis patients in Canada

International Journal of Drug Policy, Volume 86, December 2020


Philippe Lucas, Susan Boyd, M-J Milloy and Zach Walsh

Author affiliations: University of Victoria, University of British Columbia, Tilray, Canadian Institute for Substance Use Research, British Columbia Centre on Substance Use, Centre for the Advancement of Psychological Science and Law


  • Following medical cannabis initiation, 44% (n=419) of participants reported decreases in alcohol use frequency over 30 days, and 34% (n=323) decreased the number of standard drinks they had per week.
  • Younger age (<55 years old) and higher rates of alcohol use prior to medical cannabis initiation were associated with greater odds of reducing alcohol.
  • Specific intention to use medical cannabis to reduce alcohol consumption resulted in greater odds of reducing and/or ceasing use altogether.


Evidence details how cannabis can influence the use of other psychoactive substances, including prescription medications, alcohol, tobacco and illicit drugs, but very little research has examined the factors associated with these changes in substance use patterns.

This paper explores the self-reported use of cannabis as a substitute for alcohol among a Canadian medical cannabis patient population.


Data was derived from a survey of 2102 people enrolled in the Canadian medical cannabis programme. We included 973 (44%) respondents who reported using alcohol on at least 10 occasions over a 12 month period prior to initiating medical cannabis, and then used retrospective data on the frequency and amount of alcohol use pre-and post-medical cannabis initiation to determine which participant characteristics and other variables were associated with reductions and/or cessation of alcohol use.


Overall, 419 (44%) participants reported decreases in alcohol usage frequency over 30 days, 323 (34%) decreased the number of standard drinks they had per week, and 76 (8%) reported no alcohol use at all in the 30 days prior to the survey.

Being below 55 years of age and reporting higher rates of alcohol use in the pre-period were both associated with greater odds of reducing alcohol use, and an intention to use medical cannabis to reduce alcohol consumption was associated with significantly greater odds of both reducing and ceasing alcohol use altogether.


Our findings suggest that medical cannabis initiation may be associated with self-reported reductions and cessation of alcohol use among medical cannabis patients.

Since alcohol is the most prevalent recreational substance in North America, and its use results in significant rates of criminality, morbidity and mortality, these findings may result in improved health outcomes for medical cannabis patients, as well as overall improvements in public health and safety.


Study shows cannabis use leads to reduction in alcohol use, but are we just swapping one vice for another?


Reductions in alcohol use following medical cannabis initiation: results from a large cross-sectional survey of medical cannabis patients in Canada


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