York researchers publish study on cannabis-related acute care

Operation table in hospital

By Alexander Huls, deputy editor, YFile

A new paper by York University researchers, titled “Disparities in cannabis-related emergency department visits across depressed and non-depressed individuals and the impact of recreational cannabis policy in Ontario, Canada,” was published in the journal Psychological Medicine, and considers the prevalence of cannabis use among people with depression, the possible resulting risk of cannabis-related emergency department (ED) visits and whether legalization may lead to more adverse events.

Antony Chum
Antony Chum

With $295,000 in funding from the Canadian Institutes of Health Research, the study is the first of its kind to examine cannabis-related acute care rates and disparities in people with depression versus people without depression. Its aim was to better understand exactly how significant rates of ED visits were, then use subsequent findings to consider how those rates have been impacted since the legalization of marijuana in Canada in 2018 with the federal Cannabis Act.

“Hospital services represent one of the largest sources of public spending. We wanted to understand whether there are any ways to do cannabis legalization in a way that can help reduce some of these expenditures and adverse health events,” says Antony Chum, assistant professor in the Faculty of Health and Canadian Research Chair, of the desired outcome.

The study examined three time periods: the pre-legalization period, from October 2015 to 2018; phase one of legalization, from October 2018 to February 2020; and phase two, from March 2020 onwards.

The first stage of the study, indeed, found that people with depression in Ontario have a four times higher risk of cannabis-related acute care. But the research team discovered something unexpected in the data since 2018.  

Chungah Kim
Chungah Kim

“Probably the biggest surprise is that recreational cannabis legalization wasn’t associated with a subsequent increase in ED visits in this depressed group,” says Chungah Kim, postdoctoral researcher at the School of Kinesiology and Health Science.

“It’s not to say that this group are not at risk, or additional risk, compared with general population,” adds Chum. “But when cannabis became more available through legalization, we didn’t see a subsequent increase.”

Chum, Kim, and the rest of the team hope the study helps raise awareness around the risks of mental health and excessive cannabis use, as well as promotes potential policy considerations and adjustments.  

“The biggest takeaway is that the study highlights the importance of integrating mental health support with screening in the context of cannabis legalization. I think that policy-makers should consider initiatives, for example, that promote integration of mental-health services for cannabis use screening in primary care. This can help identify people with depression who might be at risk for cannabis-related adverse events, and provide appropriate support and intervention programs,” says Chum.