Epilepsy and seizure disorders
Prescription CBD has strong RCT evidence in three specific syndromes. Dispensary products do not.
What the evidence says
Substantial RCT evidence for prescription purified CBD (Epidiolex) in LGS, Dravet syndrome, and TSC. This does not extend to dispensary CBD products. NASEM 2017 predates these trials.
This is the clearest example of why the source of a cannabinoid matters. Epidiolex, a purified prescription CBD, is FDA-approved for seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex in patients one year and older. That approval rests on randomised controlled trials.
NASEM in 2017 found insufficient evidence for cannabis in epilepsy — but the Epidiolex trials postdate that assessment, so the NASEM conclusion should not be quoted as current for this indication.
None of this transfers to dispensary CBD. Epidiolex doses run to 25 mg/kg/day or higher, with liver enzyme monitoring, and it has clinically significant interactions — notably a threefold increase in the active metabolite of clobazam.
We do not recommend cannabis for this
Rather than suggest a product profile, we are telling you the evidence points the other way. Talk to a clinician about options with better support.
Talk to a doctor if
- • Always — seizure disorders require neurological care
- • Do not substitute dispensary CBD for prescribed antiepileptic medication
- • A seizure lasting more than 5 minutes is a medical emergency
Related conditions
- Multiple sclerosis spasticityMuscle stiffness and spasm in multiple sclerosis. Substantial evidence for patient-reported improvement; weaker for clinician-measured.
- Tourette syndromeTic disorder. Limited evidence for THC capsules.
- DementiaNASEM found limited evidence that cannabinoids are INEFFECTIVE for dementia symptoms.
- ADHDAttention-deficit/hyperactivity disorder. No supporting evidence, and acute cannabis use impairs attention.
Sources
- Epidiolex (cannabidiol) oral solution, prescribing information, revised 05/2026. NDA 210365.Accessed 2026-08-15.
- U.S. Food and Drug Administration. FDA Regulation of Cannabis and Cannabis-Derived Products, Including Cannabidiol (CBD).Accessed 2026-08-15.
- NASEM 2017, Committee Conclusions (summary PDF of all evidence-tier conclusions).Accessed 2026-08-15.