Measuring cannabis use among young Canadians before and after legalization

September 27, 2023 | Sarah Clark

A new survey of cannabis users in Canada shows that legalization lowered usage rates among some and increased for others.

Despite concerns that cannabis legalization in Canada would cause an increase in cannabis use, a new study says rates of use among high-risk young adults showed an overall decrease in the first few years of legalization. Those who reported never using cannabis before legalization didn’t show significant increases after legalization.

Many who reported high rates of cannabis use prior to legalization reported consuming less in the years after legalization. In contrast, some who initially reported using cannabis infrequently prior to legalization increased their use post-legalization.

The new study from researchers in Canada and the US looked at rates of reported cannabis use among high-risk young adults in Ontario, Canada, aged 19.5 to 23 years.

More than 600 participants who satisfied specific criteria for substance use were surveyed every four months for the three years between February 2017 and February 2020, with three surveys conducted pre-legalization and after legalization. The data was analyzed from March to May 2023.

Of those surveyed, people who reported using cannabis frequently prior to cannabis being legalized showed significant reductions in use and consequences over time. The report notes that this likely reflects an “aging out pattern” for younger users who use cannabis less as they get older. It also highlights no significant negative outcomes regarding cannabis use or associated harms within the group connected to legalization.

While some use increased and some use decreased following legalization, “occasional use” was the most commonly reported category before legalization and “no use” was the most commonly reported category after legalization.

The “occasional cannabis use” category showed the most change. Only 83 of the 207 who reported occasional use prior to legalization reported the same following legalization. Another 66 of those switched to reporting no use, while 47 increased to “regular use.”

Despite this relatively positive news, the study also cautions that some participants did exhibit notable increases in the frequency of cannabis use, and that the majority of those who reported frequent use of cannabis prior to legalization reported no decrease following legalization, noting that “the determinants of escalation and persistence of high-frequency cannabis use in young adults warrants further examination.”

The study also highlights that cannabis use pre-legalization in Canada was fairly normalized, meaning that legalization itself may have had little impact on public perception of any potential risks.

More than half (346) of those surveyed identified as female, while 273 identified as male. The mean age was just over 21, with about half holding a bachelor’s degree or higher.