It has been long considered that cannabis leads to an increase in suicidal behaviour among patients with psychiatric disorders. However, according to the study led by the McMaster University, it is found that there is no significant association between cannabis use and suicidal behaviour in people with psychiatric disorders. The study findings contrasted with pre-existing data that shows the drug is linked to an increased chance of suicidal behaviour in the general population.

However, based on a small subset of participants, researchers did note the heaviness of cannabis use increased risk of suicidal behavior in men, suggesting a closer follow-up by medical professionals of those patients. "In what we believe to be a first, this study seeks to understand how cannabis use impacts suicide attempts in men and women with psychiatric disorders who are already at a heightened risk of attempting suicide," said Zainab Samaan, the lead author. "We know there is a high rate of cannabis use among this population and wanted to better understand any potential correlation to suicidal behaviour." Cannabis is the most commonly used illicit substance worldwide, and its consumption is expected to increase as more jurisdictions, including Canada, legalise its recreational use.