Use of psychedelics is on the rise in Canada. Doctors are starting to look at long-term risks, benefits

CBC

03-03-2025

WARNING: This story mentions suicide.
People who take prohibited psychedelics such as psilocybin or LSD and go to the emergency department for care show a higher risk of death within five years compared with Canada's general population, a new study suggests.
Psychedelics are a subclass of hallucinogenic drugs.
In the last 10 years, use of drugs such as ketamine, psilocybin, ayahuasca, and MDMA or ecstasy increased in Canada and the United States. In the U.S., the percentage of people reporting they used hallucinogens more than doubled from 3.8 per cent in 2016 to 8.9 per cent in 2021.
Use varies widely, from microdosing psilocybin, the psychoactive ingredient in magic mushrooms as part of supervised treatment, to recreational use of the illegal substances.
Dr. Daniel Myran, a family physician and researcher at the University of Ottawa, recognized that in Canada, an estimated 5.9 per cent of people used a psychedelic such as psilocybin in 2023, with use as high as 13.9 per cent in people aged 20–24. It's a trend he sees among his own patients.
In Monday's issue of the Canadian Medical Association Journal, Myran and his team start to look at the potential long-term effects of using hallucinogens, specifically risk of death.
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"We have a huge amount of hype and buzz about psychedelic-assisted therapy," Myran said. In psychedelic-assisted therapy, psychedelics such as psilocybin are combined with psychotherapy to treat post-traumatic stress disorder (PTSD) and treatment-resistant depression.
When Myran asks people in his practice why they're interested in psychedelics, some have the notion it'll help their mental health and that there aren't a lot of risks — but there's no clear proof that's the case, he says, given clinical trials exclude individuals who may be at higher risk of poor outcomes.
"I think that we just don't have that degree of data or certainty."
Study looked at ER trips, hospitalizations
To better understand if there is an association between misuse of hallucinogens and increased risk of death, researchers looked at the subset of users who had interacted with the medical system, using health care data held by ICES, Ontario's health research institute. They examined emergency department visits, hospitalizations, and outpatient physician visits for more than 11.4 million people in Ontario aged 15 to 105.
Of the total group, 7,954, or less than one tenth of a per cent, sought acute care for hallucinogen use.
The people who used hallucinogens and went to emergency were having bad reactions like uncomfortable hallucinations or a severe anxiety attack. "They are a group that's at really high risk and they probably merit close observation, interventions and thoughts about what can you do to reduce the risk," said Myron, who is also a public health and preventive medicine researcher with ICES.
Within five years, 482 (6.1 per cent) of people seeking acute care involving hallucinogens died, compared with 460 (0.6 per cent) of those in the general population of the same age and sex, the researchers reported.
It's important to note, Myron said, that pattern doesn't tell us anything about cause and effect — and whether hallucinogens played a role in the deaths.
But when the researchers looked at causes of death for some hints, they found associations with suicide, other drug poisonings, lung disease and cancer, which Myron said probably reflects higher rates of smoking among those using hallucinogens.
"Features like suicide make me much more worried about is this capturing some element of hallucinogens?" said Myron, given self harm was one of the elevated causes of death observed in the study.
The study had some limitations. The researchers didn't know what kind of hallucinogen people were taking or how they took it.
People who are in the emergency department or hospitalized because of hallucinogen use also tend to have chronic health conditions such as asthma, high blood pressure and emergency department visits for depression, compared with the general population. They're also more likely to have received care for substance use problems, the researchers said.
"The findings highlight the need for ongoing investigation and dissemination of both potential benefits and risks from hallucinogen use, particularly for use outside clinical trial settings, given rapid increases in general population use," the study's authors wrote.
Medical supervision urged
Dr. Jennifer Swainson, an associate clinical professor at the University of Alberta and a psychiatrist at the Misericordia Community Hospital in Edmonton, prescribes and studies ketamine for treatment-resistant depression as part of clinical trials.
To put the Ontario findings in context, Swainson compared the 7,000 hospital visits reported among hallucinogen users in the study to the almost 400,000 for alcohol and more than 70,000 each for opioids and stimulants such as methamphetamine.
"I think what the public needs to take away is that if these drugs are abused or misused outside of proper medical supervision, there are risks associated with them, but also not to overcall it," said Swainson, who was not involved in the CMAJ study.
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These drugs affect the brain, Swainson said, and the effects will differ depending on a person's underlying mental health and family history of psychosis or risks related to substance use.
There are also different categories of use, several physicians said.
If someone is prescribed ketamine by their physician for their depression or PTSD and they're having follow ups with a doctor, those aren't the ones who have the higher risk of death identified in the study, she said.
Swainson said there's a large movement of underground use of hallucinogens, both recreationally and "in pseudo-therapeutic settings," where an individual guides others on different psychedelic experiences under the premise that it will be therapeutic.
Swainson is working with psychedelic health researchers in Kingston, Ont., to look at what measures should be in place in clinical trials to look at potential abuse liability risks.