A large population-based cohort study in Ontario found that patients requiring acute hospital care for hallucinogen use had a heightened risk of mortality.

In the study, published in Canadian Medical Association Journal, investigators analyzed data from over 11.4 million individuals. They identified 7,953 cases of hallucinogen-related emergency department (ED) visits or hospital admissions between 2006 and 2022. They found a 2.6-fold increased risk of mortality within 5 years among those hospitalized for hallucinogen-related issues compared with the general population (hazard ratio [HR] = 2.57, 95% confidence interval [CI] = 2.09–3.15). These patients had a significantly higher likelihood of dying from suicide (HR = 5.23, 95% CI = 1.38–19.74), unintentional drug poisoning (HR = 2.03, 95% CI = 1.02–4.05), respiratory disease (HR = 2.46, 95% CI = 1.18–5.11), and cancer (HR = 2.88, 95% CI = 1.61–5.14).

"Requiring hospital-based care for hallucinogen use was associated with increases in risk of death relative to the general population, particularly from suicide. These findings should be considered in clinical and policy decision-making, given the increasing use of hallucinogens and associated problematic use," said lead study author Daniel T. Myran, MD, MPH, of the Department of Family Medicine at the University of Ottawa, and his colleagues.

Even after excluding patients with comorbid mental health or substance use disorders, the mortality risk remained elevated (HR = 3.25, 95% CI = 2.27–4.63). The most common hallucinogens linked to these hospitalizations included lysergic acid diethylamide, psilocybin, phencyclidine, ketamine, and 3,4-methylenedioxymethamphetamine, with primary reasons for admission being harmful use (35.1%), poisoning (20.9%), intoxication (18.8%), and withdrawal (13.0%).

Compared with those with alcohol-related acute care visits, patients hospitalized for hallucinogen use had a higher mortality risk (HR = 1.12, 95% CI = 1.01–1.24) but a lower risk compared with those with opioid-related hospitalizations (HR = 1.36, 95% CI = 1.24–1.50).

With hallucinogen use increasing, the study highlighted the need for further research into associated risks, particularly in nonmedical settings.

Full disclosures are detailed in the study.