Meta-analysis confirms CBD reduces seizures in Dravet syndrome

A meta-analysis of three randomized trials found adjunctive CBD increased the chance of achieving 50% seizure reduction by 69% in Dravet syndrome patients.

Lattanzi, Simona et al.·CNS drugs·2020·Strong EvidenceMeta-Analysis
RTHC-02673Meta AnalysisStrong Evidence2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Meta-Analysis
Evidence
Strong Evidence
Sample
N=359

What This Study Found

Pooling three RCTs with 359 participants (228 CBD, 131 placebo), adjunctive CBD was associated with a 69% higher likelihood of achieving 50% or greater reduction in convulsive seizures (RR 1.69, 95% CI 1.21-2.36, p=0.002). However, CBD also led to higher treatment discontinuation (RR 3.12) and side effects including somnolence, decreased appetite, diarrhea, and elevated liver enzymes.

Key Numbers

3 RCTs; 359 participants; 50% responder rate RR 1.69 (p=0.002); treatment discontinuation RR 3.12; common AEs: somnolence, appetite decrease, diarrhea, elevated liver enzymes.

How They Did This

Systematic review and meta-analysis of three randomized, placebo-controlled, double-blind trials of plant-derived pharmaceutical CBD (Epidiolex) as adjunctive treatment for Dravet syndrome seizures.

Why This Research Matters

Dravet syndrome is among the most severe drug-resistant epilepsies. This meta-analysis provides the highest level of evidence confirming that CBD offers meaningful seizure reduction for these patients.

The Bigger Picture

This meta-analysis helped solidify the evidence base that led to regulatory approval of CBD for Dravet syndrome in multiple countries. It represents one of the clearest success stories for cannabinoid medicine.

What This Study Doesn't Tell Us

Only three trials available; relatively short treatment periods; all used the same pharmaceutical CBD formulation (Epidiolex), so results may not generalize to other CBD products.

Questions This Raises

  • ?Can longer treatment maintain seizure reduction?
  • ?How do liver enzyme elevations change with prolonged use?

Trust & Context

Key Stat:
69% higher chance of 50%+ seizure reduction with CBD (RR 1.69)
Evidence Grade:
Strong: meta-analysis of three randomized, placebo-controlled, double-blind trials.
Study Age:
Published 2020.
Original Title:
Adjunctive Cannabidiol in Patients with Dravet Syndrome: A Systematic Review and Meta-Analysis of Efficacy and Safety.
Published In:
CNS drugs, 34(3), 229-241 (2020)
Database ID:
RTHC-02673

Evidence Hierarchy

Meta-Analysis / Systematic ReviewCombines many studies into one answer
This study
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / Observational
Case Report / Animal Study

Combines results from multiple studies to find an overall pattern.

What do these levels mean? →

Frequently Asked Questions

How much does CBD reduce seizures in Dravet syndrome?

Patients on CBD were 69% more likely to achieve at least 50% seizure reduction compared to placebo (RR 1.69, p=0.002).

What are the main side effects?

Somnolence, decreased appetite, diarrhea, and elevated liver enzymes. Treatment was discontinued in 9% of CBD patients vs. 2.3% on placebo.

Read More on RethinkTHC

Cite This Study

RTHC-02673·https://rethinkthc.com/research/RTHC-02673

APA

Lattanzi, Simona; Brigo, Francesco; Trinka, Eugen; Zaccara, Gaetano; Striano, Pasquale; Del Giovane, Cinzia; Silvestrini, Mauro. (2020). Adjunctive Cannabidiol in Patients with Dravet Syndrome: A Systematic Review and Meta-Analysis of Efficacy and Safety.. CNS drugs, 34(3), 229-241. https://doi.org/10.1007/s40263-020-00708-6

MLA

Lattanzi, Simona, et al. "Adjunctive Cannabidiol in Patients with Dravet Syndrome: A Systematic Review and Meta-Analysis of Efficacy and Safety.." CNS drugs, 2020. https://doi.org/10.1007/s40263-020-00708-6

RethinkTHC

RethinkTHC Research Database. "Adjunctive Cannabidiol in Patients with Dravet Syndrome: A S..." RTHC-02673. Retrieved from https://rethinkthc.com/research/lattanzi-2020-adjunctive-cannabidiol-in-patients

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.