Overview
- The Epilepsia paper published Sept. 28, 2026 analyzed 64 adults with drug‑resistant epilepsy admitted to a tertiary epilepsy monitoring unit and compared 22 people who used cannabis ≥20 days per month with 42 nonusers.
- Frequent users had more than twice the annual rate of convulsive (focal to bilateral tonic‑clonic) seizures and reached specialized inpatient care much faster, averaging about 5 years from first seizure versus about 18 years for nonusers.
- Despite severe seizure patterns, frequent users’ MRI scans were largely normal, leading authors to suggest chronic high‑THC exposure may disrupt neural circuit activity rather than cause visible structural damage.
- The study is retrospective, small, and relies on self‑reported use, so it cannot prove causation; the authors note limitations including selection bias to a tertiary center and incomplete exposure measurement.
- Study authors and clinicians say the finding warrants screening and counseling of patients who use cannabis and that planned multisite, prospective trials with toxicology will test whether stopping use or THC itself changes outcomes.