Psychedelic use linked to increased risk of schizophrenia, study finds

Ottawa, ON, November 13, 2024 – Individuals with emergency department visits involving hallucinogen use are at high risk of developing schizophrenia, according to a new study from researchers at ICES, The Ottawa Hospital, University of Ottawa’s Department of Family Medicine, and Bruyère Health Research Institute. 

These findings come as psychedelics, a type of hallucinogen, grow in popularity across North America in both recreational and therapeutic contexts. Hallucinogens include drugs such as psilocybin, LSD, DMT (Ayahuasca), and MDMA (Ecstasy). 

The study, which followed over 9.2 million individuals in Ontario, Canada, found that those with a hallucinogen-related emergency department (ED) visit had a 21-fold increased risk of developing schizophrenia compared to the general population. 

Even after considering an individual’s co-occurring substance use and mental health disorders, the study found a 3.5-fold increased risk of schizophrenia. 

“Our findings underscore a concerning link between hallucinogen use that requires care in the emergency room and increased risk of schizophrenia,” says Dr. Daniel Myran, a Canada Research Chair in Social Accountability at the University of Ottawa, ICES Adjunct Scientist, Investigator at the Bruyère Health Research Institute, and Clinician Investigator at The Ottawa Hospital.  

“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,” adds Myran. 

Published in the journal JAMA Psychiatry, researchers analysed health data for people aged 14 to 65 years old living in Ontario from 2008 to 2021.  

The authors looked at changes in the number of ED visits involving hallucinogens over time, along with the risk of being diagnosed with schizophrenia after such visits. 

Key findings: 

• While annual rates of ED visits involving hallucinogens were stable between 2008 and 2012, they increased by 86% between 2013 and 2021. 

• Within three years of an ED visit involving hallucinogens, 4% of individuals were diagnosed with schizophrenia, compared to 0.15% for members of the general population followed for the same period—a risk 21 times higher.  

• Individuals with ED visits involving hallucinogens were at 4.7 and 1.5 times higher risk of schizophrenia respectively compared to individuals with ED visits involving alcohol and cannabis.  

The authors emphasize that their findings do not establish a causal link between hallucinogen use and schizophrenia and that much more information is needed about risks associated with different types and use patterns of hallucinogens. However, the study highlights risks associated with hallucinogen use that requires ED care and potentially in individuals with underlying susceptibility to psychosis or schizophrenia. The authors also emphasize the importance of further studies and public health measures to better understand and mitigate these risks. 

“Clinical trials of psychedelic-assisted psychotherapy 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,” says Myran.  

“It is also important that we are able to identify those at risk of developing serious adverse events from psychedelics requiring emergency care, so that future trials can screen for baseline risk of complications of psychedelic use and inform safe recruitment practice,” says Dr. Marco Solmi, Director of Research at uOttawa Psychiatry Department and Medical Director of the On Track Early Intervention Service for psychosis in Ottawa. 

The article “Risk of Schizophrenia Spectrum Disorder in Individuals with Emergency Department Visits Involving Hallucinogen Use,” was published in JAMA Psychiatry. 

ICES is an independent, not-for-profit research and analytics institute that uses population-based health information to produce knowledge on a broad range of healthcare issues. ICES leads cutting-edge studies and analyses evaluating healthcare policy, delivery, and population outcomes. Our knowledge is highly regarded in Canada and abroad and is widely used by government, hospitals, planners, and practitioners to make decisions about healthcare delivery and to develop policy. For the latest ICES news, follow us on X, formerly Twitter: @ICESOntario 

The Ottawa Hospital (TOH) is one of Canada’s top learning and research hospitals where we are guided by our vision to provide the world-class and compassionate care we would all want for our loved ones. Our multi-campus hospital, affiliated with the University of Ottawa, is home to the Regional Trauma Centre and Cancer Centre, and to discoveries that are adopted globally. Backed by generous support from the community, we are focused on reshaping the future of health care to improve the health of our diverse population of patients from Eastern Ontario, Western Quebec, and Nunavut. For more information about The Ottawa Hospital, visit OttawaHospital.on.ca.   

The Bruyère Health Research Institute conducts world-class research to maximize quality of life and shape the future health care. As part of an academic sciences centre, our research supports evidence-based care with a focus on aging and long-term care, palliative care, rehabilitation and recovery, and social accountability. To learn more, visit http://www.bruyere.org.  

The University of Ottawa is home to over 50,000 students, faculty and staff, who live, work and study in both French and English. Our campus is a crossroads of cultures and ideas, where bold minds come together to inspire game-changing ideas. We are one of Canada’s top 10 research universities—our professors and researchers explore new approaches to today’s challenges. One of a handful of Canadian universities ranked among the top 200 in the world, we attract exceptional thinkers and welcome diverse perspectives from across the globe. www.uottawa.ca 

FOR FURTHER INFORMATION PLEASE CONTACT: 

Misty Pratt 
Senior Communications Associate, ICES 
Misty.Pratt@ices.on.ca  
343-961-6982