“In other words, the majority of cannabis was consumed by a small proportion of users who used cannabis daily,” Dr Chan said.
“This suggests harm caused from cannabis use is likely to fall on a small proportion of users.”
Dr Chan said the findings mirrored similar studies into alcohol use, which also found a small proportion of daily users accounted for the majority of the drug consumed.
Australia has already legalised the production and use of cannabis for medicinal purposes under strict conditions, however there are also calls for recreational use to be decriminalised or legalised completely.
Dr Chan said if that were to happen the government would need to carefully consider all the implications for the small number of people who make up the bulk of the drug’s consumption.
“This research can inform how future policies can be implemented to prevent disproportionate harm in a very small number of users,” he said.
“We also know that regular cannabis use is linked to certain medical conditions such as psychosis, so we need to have corresponding infrastructure such as prevention programs to try to help these people if we legalise cannabis.”
Dr Chan said measures similar to those put in place for tobacco should be considered if cannabis were legalised, including targeted taxation and restrictions on advertising.
Support for full decriminalisation of cannabis in Australia has been slowly growing for some time, with Roy Morgan polling from October 2019 showing 42 per cent of Australians support legalisation, 9 per cent higher than four years ago.
Cannabis is the most widely used illicit drug in Australia, according to figures from the Australian Institute of Health and Welfare, with the highest proportion of users who use the drug once a week or more.
Australians aged 18 to 34 years old are the most likely to support the legalisation of cannabis, while the average age of a typical user increased from 29 in 2001 to 34 in 2016.
The UQ study has been published in the scientific journal Addiction.
Stuart Layt covers health, science and technology for the Brisbane Times. He was formerly the Queensland political reporter for AAP.