Hallucinogen-related ER visits linked to higher risk of schizophrenia, study finds

People who visit emergency rooms after using hallucinogenic drugs may face a higher risk of developing schizophrenia spectrum disorders, a new study published in JAMA Psychiatry suggests.

Hallucinogenic drugs such as LSD and MDMA have gained renewed interest in recent years, with growing attention to their potential therapeutic benefits. Some studies suggest that psychedelics could help treat conditions like alcohol use disorder and PTSD. However, concerns remain about potential mental health risks, particularly when these substances are used outside supervised clinical settings.

While previous studies have hinted at a possible link between hallucinogen use and psychosis, they were often limited by small sample sizes, highlighting the need for larger population-based research. In response, researchers set out to examine whether hallucinogen use might increase the risk of developing psychosis and schizophrenia spectrum disorders—a group of conditions marked by hallucinations, delusions, and disorganized thinking.

To conduct the study, a team led by Daniel T. Myran from the Ottawa Hospital Research Institute in Canada analyzed emergency department data from 9,244,292 individuals aged 14 to 65 years (50% female) in Ontario.

Among them, 5,217 individuals (0.1%) had an emergency visit related to hallucinogen use. These individuals were tracked over time—on average, for about five years—to see whether they later received a diagnosis of a schizophrenia spectrum disorder (SSD).

Statistical analysis revealed that people who had an emergency department visit involving hallucinogen use were 21 times more likely to develop an SSD within three years, compared to the general population.

Even after accounting for factors like age, sex, income, prior mental health conditions, and use of other substances, individuals with a hallucinogen-related ED visit still had a 3.5 times greater risk of developing an SSD.

The researchers also compared outcomes to people who had emergency visits related to other substances. Those who had ED visits involving hallucinogens faced a significantly higher risk of developing schizophrenia or a related disorder within three years compared to those with ED visits involving alcohol (4.7 times higher risk) and cannabis (1.5 times higher risk).

Myran and colleagues acknowledged limitations in their findings. “Our study could not establish a causal link between hallucinogen use requiring care in the emergency department and schizophrenia spectrum disorders, and the associations presented in this study should not be interpreted as causal in nature,” they wrote.

However, they concluded with some suggestions for clinical applications, “Our findings revealed a group that may have high risk of development of schizophrenia spectrum disorders who may benefit from close follow-up and intervention or preventative efforts.”

The study, “Emergency Department Visits Involving Hallucinogen Use and Risk of Schizophrenia Spectrum Disorder,” was authored by Daniel T. Myran, Michael Pugliese, Jennifer Xiao, Tyler S. Kaster, M. Ishrat Husain, Kelly K. Anderson, Nicholas Fabiano, Stanley Wong, Jess G. Fiedorowicz, Colleen Webber, Peter Tanuseputro, and Marco Solmi.