Summary: A new study links hallucinogen-related emergency department visits to a 21-fold increased risk of schizophrenia compared to the general population. Even after accounting for other mental health disorders and substance use, individuals faced a 3.5-fold higher risk.
Rates of hallucinogen-related ED visits surged by 86% between 2013 and 2021, highlighting the growing popularity of psychedelics. While the findings don’t prove causation, they underscore potential risks, especially for individuals predisposed to psychosis. Researchers urge caution with hallucinogen use outside controlled therapeutic settings.
Key Facts:
- Individuals with hallucinogen-related ED visits face a 21-fold higher schizophrenia risk.
- Rates of ED visits involving hallucinogens rose 86% from 2013 to 2021.
- Schizophrenia risk remains 3.5 times higher even when adjusting for other factors.
Source: ICES
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.
About this psychedelics and schizophrenia research news
Author: Misty Pratt
Source: ICES
Contact: Misty Pratt – ICES
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Emergency Department Visits Involving Hallucinogen Use and Risk of Schizophrenia Spectrum Disorder” by Daniel Myran et al. JAMA Psychiatry
Abstract
Emergency Department Visits Involving Hallucinogen Use and Risk of Schizophrenia Spectrum Disorder
Importance
Interest in and use of hallucinogens has been increasing rapidly. While a frequently raised concern is that hallucinogens may be associated with an increased risk of psychosis, there are limited data on this association.
Objectives
To examine whether individuals with an emergency department (ED) visit involving hallucinogen use have an increased risk of developing a schizophrenia spectrum disorder (SSD).
Design, Settings, and Participants
This population-based, retrospective cohort study (January 2008 to December 2021) included all individuals aged 14 to 65 years in Ontario, Canada, with no history of psychosis (SSD or substance induced). Data were analyzed from May to August 2024.
Exposure
An incident ED visit involving hallucinogen use.
Main Outcomes and Measures
Diagnosis of SSD using a medical record–validated algorithm. Associations between ED visits involving hallucinogens and SSD were estimated using cause-specific adjusted hazard models. Individuals with an incident ED visit involving hallucinogens were compared with members of the general population (primary analysis) or individuals with ED visits involving alcohol or cannabis (secondary analysis).
Results
The study included 9 244 292 individuals (mean [SD] age, 40.4 [14.7] years; 50.2% female) without a history of psychosis, with a median follow-up of 5.1 years (IQR, 2.3-8.6 years); 5217 (0.1%) had an incident ED visit involving hallucinogen use.
Annual rates of incident ED visits involving hallucinogens were stable between 2008 and 2012 and then increased by 86.4% between 2013 and 2021 (3.4 vs 6.4 per 100 000 individuals).
Individuals with ED visits involving hallucinogens had a greater risk of being diagnosed with an SSD within 3 years compared with the general population (age- and sex-adjusted hazard ratio [HR], 21.32 [95% CI, 18.58-24.47]; absolute proportion with SSD at 3 years, 208 of 5217 with hallucinogen use [3.99%] vs 13 639 of 9 239 075 in the general population [0.15%]).
After adjustment for comorbid substance use and mental health conditions, individuals with hallucinogen ED visits had a greater risk of SSD compared with the general population (HR, 3.53; 95% CI, 3.05-4.09). Emergency department visits involving hallucinogens were associated with an increased risk of SSD within 3 years compared with ED visits involving alcohol (HR, 4.66; 95% CI, 3.82-5.68) and cannabis (HR, 1.47; 95% CI, 1.21-1.80) in the fully adjusted model.
Conclusions and Relevance
In this cohort study, individuals with an ED visit involving hallucinogen use had a greater risk of developing an SSD compared with both the general population and with individuals with ED visits for other types of substances. These findings have important clinical and policy implications given the increasing use of hallucinogens and associated ED visits.
