Just 10% of users consumed about two-thirds of all the cannabis used in Canada in 2018, according to a study headed by a Northern Medical Program professor.
Dr. Russ Callaghan and his team looked at data from the 2018 National Cannabis Survey, which assessed patterns of cannabis use among Canadians at least 15 years old.
“The findings are similar to those in the alcohol field, where we have found that a small subgroup of drinkers usually consumes the majority of alcohol in the population,” Callaghan said.
The team also found that males reported consuming 60 per cent of the cannabis consumed and males 15-34 years old were disproportionately represented in the heaviest-using subgroups.
“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,” Callaghan said.
He said future studies will look at characteristics of the heaviest-using cannabis user group, as well as assess how cannabis-related harms are distributed in Canadian society across individuals using different quantities.
Alcohol-related studies have found that five to 10 per cent of drinkers consume a majority of the volume.
There is also some evidence that most of the alcohol-related harms in societies are not found in the group of heaviest-drinking individuals, but rather in the much more numerous low-to-moderate-drinking groups.
The finding has been used as the basis for developing interventions for the entire population rather than on strategies designed for the heaviest-using subgroups.
"At this time, we don’t know if the same pattern exists in relation to cannabis as it does for alcohol,” Callaghan said.
The team was made up of researchers from UNBC, the University of British Columbia, the Centre for Addiction and Mental Health and the Canadian Institute for Substance Use Research at the University of Victoria.
[Reader's Note: This is the updated version of an earlier story that misreported that one-third of cannabis was consumed by 10% of users.]