Three randomized controlled trials found CBD produced 38-41% median seizure reduction in Dravet and Lennox-Gastaut syndromes, with a 39-46% responder rate, performing comparably to established anti-epileptic drugs.
Parents of children with epilepsy, pediatric neurologists, and anyone interested in evidence-based cannabinoid therapeutics.
38-41% seizure reduction
What the researchers found
CBD produced a 38-41% median reduction in all seizures compared to 13-19% on placebo in three RCTs for Dravet and Lennox-Gastaut syndromes. Responder rates (50% seizure reduction) were 39-46% for CBD versus 14-27% for placebo. CBD was well tolerated, with sedation, diarrhea, and decreased appetite as the most common side effects.
Why it matters
This review confirmed that CBD has crossed the threshold from anecdotal remedy to evidence-based treatment for specific severe childhood epilepsies, with efficacy comparable to drugs that have been used for decades.
The numbers in context
38-41% median reduction in all seizures (vs 13-19% placebo). 39-46% responder rate at 50% seizure reduction (vs 14-27% placebo). Common adverse effects: sedation, diarrhea, decreased appetite.
How the study worked
Review of three randomized, placebo-controlled, double-blind clinical trials examining pharmaceutical-grade CBD in Dravet syndrome and Lennox-Gastaut syndrome, with additional context on CBD pharmacology and clinical considerations.
What this study cannot tell us
The trials focused on only two epilepsy syndromes (Dravet and Lennox-Gastaut). CBD mechanism of action remains unknown. Sedation from CBD-benzodiazepine interaction complicates interpretation of some side effects.
How to read the evidence
Rated strong because the review synthesizes three randomized, placebo-controlled, double-blind trials, the gold standard of clinical evidence.
When this study was published
Published in 2019, shortly after FDA approval of Epidiolex. Additional clinical experience has accumulated since.
The bigger picture
CBD became the first cannabis-derived compound to receive FDA approval (as Epidiolex). Its demonstrated efficacy in the most rigorous trial designs available set a precedent for cannabinoid therapeutics and shifted the conversation from "Does it work?" to "For which conditions?"
Questions still open
- Will CBD prove effective for other epilepsy types? What is its mechanism of action? How should benzodiazepine doses be adjusted when adding CBD to reduce sedation?
Common questions
How effective is CBD for childhood epilepsy?
What are the side effects of CBD for epilepsy?
Does CBD work for all types of epilepsy?
Read the original research
Efficacy of cannabinoids in paediatric epilepsy.
Developmental medicine and child neurology, 61(1), 13-18
Citation
Ali, Shayma; Scheffer, Ingrid E; Sadleir, Lynette G. (2019). Efficacy of cannabinoids in paediatric epilepsy.. Developmental medicine and child neurology, 61(1), 13-18. https://doi.org/10.1111/dmcn.14087
Explore the wider topic
- CBD Oil Quality Guide: How to Avoid Snake Oil
- Anxiety After Quitting Weed: When to Consider Medication
- Cannabis for Chemotherapy Nausea: What the Evidence Actually Shows
- Cannabis for Chronic Pain: What the Research Actually Supports
- Cannabis and Epilepsy: The Epidiolex Story and What It Means
- Does CBD Actually Work for Anxiety? What the Evidence Shows
- Does CBD Help with Weed Withdrawal? What Studies Show
- CBD vs THC: The Differences That Actually Matter
- The Proven Medical Benefits of Cannabis: What Research Supports
- Quitting Weed Before Surgery
- Weed and Medications: What Changes When You Quit
- Quitting Weed During Pregnancy: What You Need to Know
- Quitting Weed While Pregnant: What You Need to Know
- Cannabis and Older Adults: Risks Seniors Should Know
- Cannabis and Breastfeeding: THC in Breast Milk