The Potential Proconvulsant Effects of Cannabis: a Scoping Review

Authors

Eric E. Kaczor, Division of Medical Toxicology, Department of Emergency Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA. erickacz428@gmail.com.
Kevin Greene, Division of Medical Toxicology, Department of Emergency Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
Jennifer Zacharia, Department of Emergency Medicine, Maine Medical Center, Tufts University School of Medicine, Portland, ME, USA.
Laura Tormoehlen, Departments of Neurology and Emergency Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
Mark Neavyn, Department of Emergency Medicine, Maine Medical Center, Tufts University School of Medicine, Portland, ME, USA.
Stephanie Carreiro, Division of Medical Toxicology, Department of Emergency Medicine, University of Massachusetts Medical School, Worcester, MA, USA.

Document Type

Article

Publication Date

3-29-2022

Journal Title

Journal of medical toxicology : official journal of the American College of Medical Toxicology

Abstract

INTRODUCTION: Cannabis' effect on seizure activity is an emerging topic that remains without consensus and merits further investigation. We therefore performed a scoping review to identify the available evidence and knowledge gaps within the existing literature on cannabis product exposures as a potential cause of seizures in humans. METHODS: A scoping review was conducted in accordance with the PRISMA Extension for Scoping Reviews guidelines. The PubMed and Scopus databases were searched over a 20-year period from the date of the database query (12/21/2020). Inclusion criteria were (1) English language original research articles, (2) inclusion of human subjects, and (3) either investigation of seizures as a part of recreational cannabinoid use OR of exogenous cannabinoids as a cause of seizures. RESULTS: A total of 3104 unique articles were screened, of which 68 underwent full-text review, and 13 met inclusion/exclusion criteria. Ten of 11 studies evaluating acute cannabis exposures reported a higher seizure incidence than would be expected based on the prevalence of epilepsy in the general and pediatric populations (range 0.7-1.2% and 0.3-0.5% respectively). The remaining two studies demonstrated increased seizure frequency and/or seizure-related hospitalization in recreational cannabis users and those with cannabis use disorder. CONCLUSIONS: This scoping review demonstrates that a body of literature describing seizures in the setting of cannabis exposure exists, but it has several limitations. Ten identified studies showed a higher than expected incidence of seizures in populations exposed to cannabis products. Based on the Bradford Hill criteria, delta-9 tetrahydrocannabinol (THC) may be the causative xenobiotic for this phenomenon.

Recommended Citation

Kaczor EE, Greene K, Zacharia J, Tormoehlen L, Neavyn M, Carreiro S. The Potential Proconvulsant Effects of Cannabis: a Scoping Review [published online ahead of print, 2022 Mar 29] [published correction appears in J Med Toxicol. 2022 Apr 21;:]. J Med Toxicol. 2022;10.1007/s13181-022-00886-3. doi:10.1007/s13181-022-00886-3