Research Library
Neurology & seizure disorders
The strongest regulatory-grade evidence in the field, including FDA-approved use.
Overview
Epilepsy is the only area where a purified cannabidiol drug has full FDA approval, based on multiple phase 3 trials.
That approval covers a prescription pharmaceutical, not hemp-derived consumer products.
What the evidence supports
- Purified CBD reduces seizure frequency in Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex.
- Effective study doses were 10–20 mg/kg/day — far above typical wellness dosing.
- Liver enzyme elevations and interactions with clobazam and valproate are well documented.
Where the evidence is thin
- Evidence for other neurological conditions (MS spasticity aside) remains preliminary.
- Consumer hemp products have not been tested at pharmaceutical doses.
Selected studies
Randomized trial · 2017
Trial of cannabidiol for drug-resistant seizures in the Dravet syndrome
Devinsky O, et al. · New England Journal of Medicine
Median convulsive seizure frequency dropped from 12.4 to 5.9 per month.
Find this study on PubMed (opens in a new tab)Randomized trial · 2018
Effect of cannabidiol on drop seizures in Lennox-Gastaut syndrome
Devinsky O, et al. · New England Journal of Medicine
Significant reduction in drop seizures versus placebo at 10 and 20 mg/kg/day.
Find this study on PubMed (opens in a new tab)