In a new study published in the journal Epilepsia, doctors examined 64 adults with drug‑resistant epilepsy who were treated at a specialized inpatient unit. One‑third of the participants reported using cannabis recreationally on most days, defined as at least 20 days per month.
Higher seizure rates among frequent users
Those frequent users suffered more than twice the number of convulsive seizures—often called “grand mal” or generalized tonic‑clonic seizures—compared with the 42 patients who did not use cannabis. Nine out of ten frequent users experienced these injury‑prone seizures, while roughly half of the non‑users avoided them entirely.
Faster medication resistance
The study also found that frequent cannabis users became resistant to antiseizure medications more quickly. On average, they were admitted to the epilepsy monitoring unit about five years after their first seizure, whereas non‑users typically waited 18 years before needing such intensive care. Despite a shorter disease history, the frequent users left the hospital on a larger regimen of antiseizure drugs.
Possible role of THC
While a purified form of cannabidiol (CBD) is FDA‑approved for certain severe epilepsies, the recreational cannabis examined in the study contains high levels of tetrahydrocannabinol (THC) and low levels of CBD. Animal research suggests CBD can suppress seizures, whereas THC may have the opposite effect. The researchers noted that many of the frequent users’ brain scans appeared normal, implying that THC’s impact on brain receptors could be driving the heightened seizure activity.
Study limitations and next steps
Lead author Dr. Aaron Struck of Washington University School of Medicine in St. Louis cautioned that the findings show a concerning association but do not prove causation. He emphasized the need for larger, multi‑region studies that incorporate objective measures of cannabis consumption rather than relying solely on patient self‑reporting.
Dr. Struck also advised clinicians to discuss cannabis use directly with epilepsy patients, especially those using it for anxiety or sleep, and to consider more predictable, regulated treatments when possible.
Implications for families
For parents of children with epilepsy, the study underscores the importance of monitoring any substance use that could exacerbate seizures. While the FDA‑approved CBD medication remains a safe, regulated option, unregulated cannabis—particularly high‑THC products—may pose additional risks.
What’s next?
The research team plans to expand the study to include states with differing cannabis‑legalization histories and to use laboratory testing at admission to verify actual THC and CBD levels. Larger data sets will help determine whether reducing or stopping cannabis use can improve seizure control.
Original reporting: KTBS 3 (Shreveport) — read the source article.
