Study finds ‘concerning link’ between hospital visits for psychedelic use and schizophrenia

Article content

People who visit emergency departments because of hallucinogenic drug use are at a heightened risk of developing schizophrenia, according to a new study.

The research, led by Dr. Daniel Myran, a Canada Research Chair in Social Accountability at the University of Ottawa, followed more than 9.2 million people in Ontario. It found that those with hallucinogen-related visits to emergency departments had a 21 times higher risk of developing schizophrenia than the general population.

Article content

The findings do not show a causal link between the use of hallucinogens such as psilocybin, LSD, DMT (Ayahuasca) and MDMA (Ecstasy), Myran emphasized, but they do offer a “timely reminder that we know very little about what some of the potential adverse effects (of hallucinogenic drug use) are.”

The study, from researchers at ICES (Institute for Clinical Evaluative Sciences), The Ottawa Hospital, uOttawa’s department of family medicine and the Bruyere Health Research Institute, comes at a time when psychedelics are growing in popularity across North America, both for therapeutic and recreational use. It was published in the journal JAMA Psychiatry.

Myran said it is clear that more information is needed about risks associated with different types and use patterns of hallucinogens.

“Our findings underscore a concerning link between hallucinogen use that requires care in the emergency room and increased risk of schizophrenia,” said Myran.

“While there is enormous enthusiasm for psychedelic-assisted therapy as a new mental health treatment, we need to remember how early and limited the data remains for both the benefits and the risks,” he said.

Article content

Article content

Among other things, the research highlighted the growing use of psychedelics. Annual rates of emergency department visits involving hallucinogens were stable between 2008 and 2012, but they increased by 86 per cent between 2013 and 2021. Researchers looked at people between 14 and 65 living in Ontario.

They found that within three years of an emergency department visit involving hallucinogens, four per cent of people were diagnosed with schizophrenia. That compares to 0.15 per cent for members of the general population who were followed for the same time period. That is a risk 21 times higher than for the general population.

They also found that people with emergency department visits involving hallucinogens were at 4.7 and 1.5 times higher risk of schizophrenia compared to individuals with emergency department visits involving alcohol and cannabis.

Psychedelic-assisted therapy – including for veterans and others struggling with PTSD – has become increasingly popular in recent years. Some research has shown positive results for the therapy in relieving symptoms of depression, anxiety and PTSD, but there remains limited data. Clinical trials are under way in Canada but there are no approved therapeutic products containing psilocybin. Health practitioners can apply for access to drugs for psychedelic-assisted psychotherapy through Health Canada’s special access program.

Article content

On its notice about access to the drugs through its special access program, Health Canada said it recognizes “the growing interest in the use of psychedelic-assisted psychotherapy and the possible psychological and physical risks to patients associated with this type of therapy.”

Myran noted that ongoing clinical trials for psychedelic-assisted therapy have safeguards “such as excluding individuals with a personal or family history of schizophrenia and close monitoring while participants use hallucinogens.

“Our findings provide a timely caution about potential risks of hallucinogen use outside of trial settings.”

Myran noted that psychedelic-assisted therapy is an emerging field.

“There is certainly promising trial evidence that psychedelic-assisted therapy may have benefits in some mental health conditions,” he said, but there is still much that is not known about both the benefits and the risks. The number of people involved in clinical trials on possible benefits of the therapy remains very small, he said.

Recently, magic mushroom (psilocybin) despensaries have popped up in cities around Canada, including in Ottawa.

Between the buzz around the promise of psychedelic-assisted therapy and easier access to some hallucinogenic drugs, Myran said he worries there will be more people trying the drugs outside of tightly controlled clinical trial settings.

While more research needs to be done on potential risks, Myran said people at high risk of schizophrenia or with prior episodes of psychosis “should be very cautious about using hallucinogens.”

Article content