Epilepsy & Seizures
The strongest clinical evidence base in cannabinoid medicine
Epilepsy represents the most robust area of clinical cannabinoid research. CBD (Epidiolex) is FDA-approved for Dravet syndrome and Lennox-Gastaut syndrome — the first cannabis-derived pharmaceutical to receive FDA approval. The evidence base here is stronger than for any other cannabinoid indication.
What the Research Shows
CBD's anticonvulsant mechanisms are distinct from its anxiolytic effects and appear to involve multiple targets: GPR55 antagonism, TRPV1 desensitization, sodium channel modulation, and adenosine reuptake inhibition. Unlike THC, CBD does not produce psychoactive effects, making it suitable for pediatric use. The landmark 2017 NEJM Phase 3 trial of CBD in Dravet syndrome showed a 38.9% reduction in convulsive seizure frequency vs. 13.3% with placebo — a result that directly supported FDA approval of Epidiolex in 2018. Subsequent trials confirmed efficacy in Lennox-Gastaut syndrome. For other epilepsy types, evidence is more limited but promising. Important caveats: CBD interacts significantly with clobazam (increasing active metabolite levels), and elevated liver enzymes are observed in a subset of patients, particularly those on valproate.
Key Findings
CBD reduces Dravet seizures by ~39% vs placebo
Well-StudiedPhase 3 RCT (NEJM 2017) — the trial that supported FDA approval of Epidiolex for Dravet syndrome.
FDA-approved for Dravet and Lennox-Gastaut
Well-StudiedEpidiolex (pharmaceutical-grade CBD) is the only FDA-approved cannabis-derived medicine for epilepsy.
CBD interacts with clobazam
Well-StudiedCBD inhibits CYP2C19, increasing clobazam's active metabolite (N-desmethylclobazam) — dose adjustment required.
Liver enzyme elevations in ~10% of patients
Well-StudiedTransaminase elevations observed, particularly with concurrent valproate. Monitoring recommended.
Featured Studies
View all in libraryCommon Questions
What We Still Don't Know
These are open research questions — areas where the evidence is insufficient or actively contested.
- 1Why do some patients with Dravet syndrome not respond to CBD?
- 2Can CBD prevent epilepsy development in high-risk patients (e.g., post-TBI)?
- 3What is the mechanism of CBD's anticonvulsant action at the molecular level?
- 4Does CBD have disease-modifying effects beyond seizure suppression?
- 5Are there genetic biomarkers that predict CBD response in epilepsy?