Legal access to cannabis for medical purposes leads to a direct reduction in alcohol consumption, suggests a new analysis by a group of researchers in the United States.
That research, which was recently published as a working paper and is in the process of submission to a peer-reviewed journal, found that U.S. counties where medical cannabis is legal experienced a 13 per cent reduction in monthly alcohol sales.
The economists behind the research used Nielsen data on alcohol sales from 2006 to 2015 as a corollary for alcohol consumption, which helped them get around the fact that people aren't very good at accurately reporting their own drinking habits. They compared that data, on a county-by-county level, to local medical cannabis laws, accounting for regional variations such as home cultivation and licensed dispensaries.
"Counties in states legalizing the use of medical marijuana experience a significant decrease in the aggregate sales of alcohol, beer and wine," wrote the authors. "Moreover, the effects are not short-lived, with significant reductions observed up to 24 months after the passage of the law."
That result "wasn't surprising, but at the same time, it wasn't something we were expecting," says Alberto Chong, a professor of economics at Georgia State University and one of the co-authors of the paper.
Previous research on this topic has been split, Chong says. Some researchers have found marijuana does act as a substitute for alcohol, while others concluded the two substances are used in a complementary way.
Chong says he and his colleagues used econometric methods and ran a series of falsification tests to check their work and determine the two substances are, in fact, substitutes. The researchers, Chong said, "feel very confident that these results are true, compared to these results that exist already that we've reviewed and we've seen, they're not as strong."Advertisement
"The policy implications are very straightforward: you should legalize marijuana," says Chong.
"It's very simple, to me. I'm not a public policy guy, but from a cost-benefit perspective it's much better to legalize marijuana than to have alcohol," he says. "If you legalize marijuana, you're going to reduce alcohol consumption, and the health effects of alcohol are much worse than those from marijuana, so you're going to save a lot of money from a health-care perspective."
The findings from the U.S. study are definitely compelling, says Rebecca Haines-Saah, an assistant professor of community health sciences at the University of Calgary.
"In terms of how they conceptualized this study and the variables and the context they're accounting for, I found it to be quite sophisticated in that they're looking at the nuanced policy changes and accounting for the fact that jurisdictions have different modes of implementation," she says.
"It sort of speaks to what we're going to see in Canada, that there will be slight (regional) variations. We can't just say, 'This is the result of cannabis legalization in Canada'; we'll need to go jurisdiction by jurisdiction based on the provincial model, but also based on the pre-existing context."
Haines-Saah cautions, however, that Canadians shouldn't necessarily expect cannabis legalization to have an equally dramatic effect on alcohol consumption in this country, since Canadian federal law has allowed access to medical cannabis since 2001.
Evidence that cannabis acts as a substitute for alcohol, she says, could also inform the current debate about whether it's acceptable to sell cannabis and liquor at the same location. (Some public-health experts have warned against that.)
Another pressing question for researchers, Haines-Saah believes, is whether cannabis might act as a substitute for other substances, as well.
"People are hopeful that there will be the substitution effect for opioid use, for people using (drugs) prescribed for chronic pain, or using in the illicit market. It's too early to know, but these are absolutely the things we need to get grants to study, because I think everyone's interested and it could show some promise for reducing population health harms."
Chong already knows what he wants to examine next: whether there's a link between legal cannabis access and obesity rates.
"You know (how) they always talk about the munchies? We would like to study that."