Meta-analysis confirmed CBD reduces seizures by 33% in treatment-resistant epilepsy
A meta-analysis of 6 randomized trials with 1,034 patients found CBD reduced seizure frequency by 33% and increased the chance of 50% seizure reduction by 20% in Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex.
Quick Facts
What This Study Found
CBD compared to placebo reduced seizure frequency by 33%, increased 50% seizure reduction by 20%, increased seizure freedom by 3%, and improved caregiver-assessed clinical impression by 21% in patients with refractory epilepsy.
Key Numbers
1,034 patients across 6 RCTs. Seizure frequency reduced 33%. Patients with 50%+ reduction increased by 20%. Seizure-free patients increased by 3%. Caregiver improvement 21%. Total adverse events increased 12%. Serious adverse events increased 16%. Treatment abandonment increased 12%. Transaminase elevation (3x+ reference) increased 15%.
How They Did This
Systematic review with meta-analysis of 6 RCTs (3 primary, 3 open-label extensions) totaling 1,034 patients with Dravet syndrome, Lennox-Gastaut syndrome, or tuberous sclerosis complex. Searched MEDLINE, Cochrane Central, and ClinicalTrials.gov through April 2022. Followed PRISMA guidelines.
Why This Research Matters
This meta-analysis provides the strongest quantitative evidence to date supporting CBD as an add-on treatment for three of the most difficult-to-treat pediatric epilepsy syndromes.
The Bigger Picture
CBD (as Epidiolex/Epidyolex) is one of the few cannabis-derived medications with robust clinical trial evidence. This meta-analysis reinforces its place in treating the most treatment-resistant forms of epilepsy.
What This Study Doesn't Tell Us
Only 6 RCTs available. The included epilepsy syndromes are rare, so generalizability to other seizure types is uncertain. The increase in serious adverse events and liver enzyme elevations is notable.
Questions This Raises
- ?Can the serious adverse event profile be managed with dose optimization?
- ?Would CBD be effective in more common forms of epilepsy?
- ?Do the open-label extension results reflect the true long-term efficacy, given the lack of blinding?
Trust & Context
- Key Stat:
- 33% reduction in seizure frequency vs placebo
- Evidence Grade:
- Strong: meta-analysis of 6 randomized controlled trials with over 1,000 patients.
- Study Age:
- Published in 2022.
- Original Title:
- Use of cannabidiol in the treatment of epilepsy: Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex.
- Published In:
- Revista da Associacao Medica Brasileira (1992), 68(10), 1345-1357 (2022)
- Database ID:
- RTHC-04223
Evidence Hierarchy
Combines results from multiple studies to find an overall pattern.
What do these levels mean? →Frequently Asked Questions
Which epilepsy syndromes were studied?
Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex, three of the most treatment-resistant forms of epilepsy.
Were there significant side effects?
Yes. CBD increased total adverse events by 12%, serious adverse events by 16%, treatment dropout by 12%, and liver enzyme elevations by 15% compared to placebo.
Does this mean CBD works for all seizures?
This evidence applies specifically to Dravet syndrome, Lennox-Gastaut, and tuberous sclerosis complex with treatment-resistant seizures. Results may not generalize to other epilepsy types.
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Cite This Study
https://rethinkthc.com/research/RTHC-04223APA
Silvinato, Antônio; Floriano, Idevaldo; Bernardo, Wanderley Marques. (2022). Use of cannabidiol in the treatment of epilepsy: Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex.. Revista da Associacao Medica Brasileira (1992), 68(10), 1345-1357. https://doi.org/10.1590/1806-9282.2022D689
MLA
Silvinato, Antônio, et al. "Use of cannabidiol in the treatment of epilepsy: Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex.." Revista da Associacao Medica Brasileira (1992), 2022. https://doi.org/10.1590/1806-9282.2022D689
RethinkTHC
RethinkTHC Research Database. "Use of cannabidiol in the treatment of epilepsy: Lennox-Gast..." RTHC-04223. Retrieved from https://rethinkthc.com/research/silvinato-2022-use-of-cannabidiol-in
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.