A small but notable study published in Epilepsia suggests that frequent cannabis use may be associated with a heavier seizure burden in adults with drug-resistant epilepsy (DRE). Researchers at Washington University Medicine in St. Louis reviewed records from 64 adults admitted to an epilepsy monitoring unit between 2019 and 2024, comparing 22 frequent cannabis users (≥20 days/month) to 42 non-users.

Frequent users showed a notably more severe clinical picture: they were more likely to experience full-body convulsive seizures and had them more often, all while being prescribed more antiseizure medications. Researchers hypothesize that THC's interaction with CB1 receptors — densely concentrated in the hippocampus — may make temporal lobe epilepsy harder to control. However, experts caution that the relationship could be bidirectional: people with more severe epilepsy may also be more likely to turn to cannabis for symptom relief.

By the Numbers:

• 90.9% of frequent cannabis users had focal to bilateral tonic-clonic seizures vs. 57.1% of non-users
• Frequent users averaged 3.00 convulsive seizures/year vs. 1.32 in non-users
• Cannabis users were discharged on 3.05 antiseizure medications vs. 2.21 for non-users

Why it matters: Clinicians treating epilepsy patients should proactively ask about cannabis use — especially high-THC products — and consider whether reducing use could improve seizure control. Larger, prospective studies are needed before firm conclusions can be drawn.