Minority of users use majority of cannabis
Only 10 per cent of cannabis users consumed the majority of cannabis in Canada in 2018, according to a new study from the University of Northern British Columbia.
Dr. Russ Callaghan and his team crunched data from the 2018 National Cannabis Survey and found that that small subset of heavy users was responsible for about twothirds of all cannabis consumed across the country last year.
“This is a pattern that is similar to the one we see in alcohol, but a bit more concentrated,” said Callaghan, the study’s lead author and a professor in the university’s medical program. “This is the first study to identify this pattern, and it may be important for public health strategies in designing interventions to reduce cannabis-related harms.”
The study aimed to examine if cannabis consumption is similar to the consumption pattern for alcohol, in which a small minority of drinkers account for a disproportionately high percentage of total alcohol consumption.
The findings came as a surprise to Callaghan. “We weren’t sure what we’d find because I know cannabis use is so prevalent in our society. But after the findings came out, it made sense that it is similar to the patterns found in alcohol.”
The study used data from a population-based survey in the first three quarters of 2018, prior to legalization.
Callaghan said there hasn’t been enough research in the cannabis field to indicate in which subset of users cannabis-related harms are concentrated. For alcohol, research has shown the harms are primarily found in the low- and moderate-using groups.
That is because there are many more low and moderate users rather than heavy users, said Callaghan, who hypothesized that the harms in cannabis would likely also follow a similar pattern to alcohol.
“From a public health perspective, if we want to reduce harm in a population, we want to see where the harms are situated,” he said.
The UNBC study also found that men reported consuming more cannabis by volume than women, at about 60 per cent versus 40 per cent. Men ages 15 to 34 are disproportionately represented among the heaviest user subgroups.
The project team included researchers from UNBC, the University of B.C., the Centre for Addiction and Mental Health, and the Canadian Institute for Substance Use Research at the University of Victoria.