Canadians who regularly use cannabis may increase their risk of developing an anxiety disorder or worsen existing anxiety symptoms, according to a new provincial study.
On Monday, researchers at the Bruyère Research Institute, University of Ottawa Department of Family Medicine, The Ottawa Hospital, and ICES released its study regarding the relationship between cannabis use and anxiety disorder. The study, published in the Lancet’s open access journal eClinical Medicine, is considered the largest study on the subject to date.
“Cannabis use has rapidly increased in Canada over the past 15 years and there is a general sense that cannabis is relatively harmless or has health benefits. Our study cautions that in some individuals, heavy cannabis use may increase their risk of developing anxiety disorders,” lead author Dr. Daniel Myran, who is a Canada research chair at the University of Ottawa and an ICES adjunct scientist, said in a press release.
The study includes over 12 million residents in Ontario between 2008 and 2019 who have received a diagnosis or treatment for anxiety.
It found that 27 per cent of individuals who visited an emergency room for cannabis use developed an anxiety disorder within three years, compared to 5.6 per cent of the general population who visited the ER for anxiety.
In addition, the study found that 12.3 per cent of individuals who had pre-existing anxiety symptoms visited an emergency room or were hospitalized because their symptoms worsened.
Researchers say that individuals of all ages who have visited the ER for cannabis use are at higher risk of developing new anxiety disorders, however the risk is much higher for younger adults between 10 to 24 years old and men.
Though it is common for some people to use cannabis to treat anxiety, researchers are warning people against it given the lack of evidence, the risk that it may delay other evidence-based treatments, and the risk that it may significantly worsen anxiety symptoms.
“Our results suggest that individuals requiring emergency department treatment for cannabis use were both at substantially increased risk of developing a new anxiety disorder and experiencing worsening symptoms for already existing anxiety disorders,” Myran, who is also an investigator at the Bruyère Research Institute, and a clinician investigator at The Ottawa Hospital, said.
