Here’s how cannabis legalization affected tobacco, alcohol and opioid use: McGill study

McGill University researcher Sarah Windle explains how legalizing cannabis has had effects on other substance use, including tobacco and alcohol.

A new study out of McGill University shows that cannabis legalization has created a mixed bag of positive and negative impacts in addition to having possible effects on other substance use.

Study lead Sarah Windle said that, as expected, medical and recreational cannabis legislation increased initiation and prevalence of use among adults.

“What we were particularly interested in is whether other substance use changes, in particular, whether there’s consequences for even legal drugs such as alcohol or tobacco, because together alcohol and tobacco actually account for about 95 per cent of substance-related mortality worldwide,” said the PhD candidate in McGill’s department of epidemiology.

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With tobacco and alcohol abuse contributing notably to cancer and cardiovascular diseases, Windle said that even small changes in the use of either could have implications on public health.

“We actually found a potential decrease in the use of tobacco products, cigarettes specifically,” she said. “We also found a potential reduction in opioid-related outcomes. These include things like opioid prescriptions and opioid sales.”

Alcohol consumption, the study found, was more complicated.

“We found a potential decrease in alcohol use following medical legalization, suggesting that some of these individuals who are using medical cannabis may actually be using cannabis in place of alcohol,” said Windle. “So, where they would have formerly drank, they’re instead using cannabis instead to replace those effects. However, following recreational cannabis legalization, we found an increase in alcohol use, particularly among young adults.”

In addition, a study found an increase in positive workplace drug tests following the opening of dispensaries. Another study found no change in those halting cannabis use.

The study involved a review of 176 studies over the past 30 years in Canada, the U.S., Europe, Uruguay and Australia. It was published in the Milbank Quarterly.

With increased use came increased hospital emergency room visits, as well as more calls to the poison centre.

Windle said the study raised questions about the relationship between cannabis and other substances post-legalization.

“Substance use is a very personal thing,” she said. “People approach it in different ways, but it’s a pervasive human experience, so it’s understandable that policies that are impacting one substance are going to impact the use of other substances, but that really depends on the individual and how they’re approaching it.”