Cannabis use in a legal context

Weeding out misconceptions about the harms and benefits of cannabis

While people have been using cannabis for thousands of years, starting in Central Asia and the Indian subcontinent, stigmatization and criminalization over the past century have made it almost impossible to properly study its effects—positive or negative.

That’s why Zach Walsh of The University of British Columbia was pleased when Canada became the second country in the world to fully legalize recreational cannabis.

“Canadians have been empowered to make personal choices about how they use one of humanity’s oldest drugs,” he said. “Legalization presents an amazing opportunity to learn more about people’s motives for using cannabis and its effects without all the social baggage.”

Personality and cannabis use

Walsh is working on a 48-month study to examine who’s using cannabis, why, and what that means for individuals and society. His research is built on the proposition that cannabis users are not all the same—and that cannabis might not affect all personality types the same way. For some, cannabis could have benefits; for others, it could be harmful.

His study follows 400 university undergraduate students, a demographic that has traditionally presented the highest rates of cannabis use. He’s using a variety of methods to collect data, from traditional interviews and laboratory tasks to more innovative methods, such as text messaging, that allow participants to report on their cannabis use in near real time. This will enable Walsh to correlate usage patterns with overall well-being, other substance use, and educational and professional success.

Informing cannabis policy

Walsh intends for his research to help inform rational, science-based cannabis policies—the same way decades of evidence have been used to determine how society manages alcohol sales and consumption.

In particular, Walsh says that with cannabis now legal and more readily available, it’s important to understand how it interacts with other substances. If it is found that increased cannabis use actually reduces harmful alcohol use, for example, governments could have an incentive to price cannabis in a way that encourages people to choose it over other, more harmful drugs.

“Canada is taking a really brave policy step,” said Walsh. “The world is watching to see what happens.”

Want to learn more?

Follow Walsh’s work at