What topics does this cannabis study cover?

This study covers research on: Epilepsy, Neuroprotection.

Where was this research published?

Published in Clinical toxicology (Philadelphia, Pa.) on June 2, 2026.

Epilepsy Neuroprotection

THC doubles seizure risk in emergency cases, study confirms

Relative odds of seizure in emergency department cases of analytically confirmed illicit substance exposure.

Clinical toxicology (Philadelphia, Pa.) • June 2, 2026 • Moderately Relevant

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AI Summary

A major study analyzing emergency department data from Australia reveals that delta-9-tetrahydrocannabinol (THC) carries a doubled risk of seizure when users are exposed to this cannabinoid compared to baseline. This research tracked 6,318 analytically confirmed illicit drug exposures from 2020-2025, representing a significant advancement over previous studies that relied on self-reported drug use. The findings showed that 7% of all cases and 8.1% of cases without protective anticonvulsant medications resulted in seizures, establishing THC as one of three drugs with notably increased seizure risk alongside cocaine and MDMA.

The study's rigorous methodology—using actual laboratory confirmation rather than patient self-reporting—provides reliable evidence for THC's association with seizure activity. Beyond cannabis, researchers found that gamma-hydroxybutyrate actually decreased seizure odds, while methamphetamine showed an unexpected protective association likely due to testing artifacts. The research underscores an important safety concern: users with seizure disorders or family histories of epilepsy should be particularly cautious with cannabis consumption, as THC exposure roughly doubled their seizure odds in this population.

These findings have significant implications for harm reduction and medical guidance. The analytical toxicology approach used here provides a more accurate picture of drug-related risks than previous epidemiological methods, enabling healthcare providers and harm-reduction programs to better counsel cannabis users about seizure risks. The doubled odds of seizure with THC exposure joins other known cannabinoid risks and highlights the need for informed consent and medical monitoring, particularly for vulnerable populations.

📄 Original Abstract

Quantification of risk of seizure from individual illicit substances has traditionally relied on self-reported exposure. This study determined risk of seizure using data from emergency department presentations with analytically confirmed illicit substance exposure. Data were extracted from the Emerging Drugs Network of Australia and Emerging Drugs Network of Australia-Victoria illicit substance exposure registries 2020-2025. Cases with analytically confirmed illicit substance exposures were categorised according to reported seizure occurrence. Odds ratios for seizure were calculated for individual drugs using three groups: individual drug including all co-detected substances, individual drug following exclusion of benzodiazepines, anticonvulsants, gabapentinoids, and individual drug following exclusion of benzodiazepines, anticonvulsants, gabapentinoids and gamma-hydroxybutyrate. Seizure occurrence in all cases (n = 6318) was 6.7% (n = 425). Seizure rate increased to 7.1% (n = 196/2748) when patients co-exposed to an anticonvulsant were excluded, and to 8.1% (n = 143/1665) with additional exclusion of gamma-hydroxybutyrate. Significantly increased odds of seizure were found for cocaine (odds ratio 3.8, 95% CI 2.5-5.8, P <0.001), 3,4-methyledioxymetafetamine (odds ratio 2.5, 95% CI 1.5-3.8, P <0.001) and delta-9-tetrahydrocannibinol (odds ratio 2.0, 95% CI 1.3-3.2, P = 0.005). Gamma-hydroxybutyrate positive cases consistently had decreased odds of seizure (odds ratio 0.58, 95% CI 0.4-0.8, P = 0.001). Methamphetamine demonstrated a consistent inverse association for seizure across all analytical groups (odds ratio 0.6-0.7), possibly reflective of high background prevalence and residual low-level detections rather than true pharmacological effect. Although positive, odds ratios for seizure for antihistamine, selective serotonin reuptake inhibitor, and ketamine exposures did not reach significance. In this cohort of analytically confirmed illicit drug exposures, cocaine, 3,4 methylenedioxymethamphetamine and delta-9 tetrahydrocannabinol were strongly associated with increased odds of seizure. Gamma-hydroxybutyrate was associated with decreased seizure odds. These findings underscore the importance of analytical toxicology surveillance in defining outcomes including seizure risk and informing harm-reduction strategies.

Paper Type

📄 Research

Publication

Journal: Clinical toxicology (Philadelphia, Pa.)
Published: June 2, 2026
PMID: 42227670
DOI: 10.1080/15563650.2026.2671976

Authors (9)

Shaun L Greene Victorian Poisons Centre, Austin Health, Melbourne, Australia.
Courtney Weber Centre for Clinical Research in Emergency Medicine, Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia.
Sarah E Hodgson Victorian Poisons Centre, Austin Health, Melbourne, Australia.
Jennifer Smith Centre for Clinical Research in Emergency Medicine, Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia.
Sam Alfred Emergency Department, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
+4 more authors