CBD Reduced Seizures by 50% or More in Children With Severe Epilepsies | Research

The takeaway

Across 14 studies involving 682 children with developmental and epileptic encephalopathies, cannabidiol reduced seizure frequency by at least 50% in at least 20% of patients in 11 of the studies reviewed.

Pediatric neurologists, families of children with severe epilepsy, and researchers in cannabinoid-based therapeutics.

What the researchers found

Pharmaceutical CBD (up to 50 mg/kg/day) achieved 50% or greater seizure reduction in at least 20% of participants in 11 of 14 included studies. Common adverse events were somnolence, appetite loss, diarrhea, fatigue, and elevated liver enzymes, mostly mild to moderate.

Why it matters

Developmental and epileptic encephalopathies are among the most treatment-resistant forms of epilepsy in children, often failing multiple medications. This systematic review confirms that CBD provides meaningful seizure reduction for a substantial minority of these children.

The numbers in context

722 records screened, 14 included. 682 total children across studies. Maximum CBD dose: 50 mg/kg/day. 11 of 14 studies reported at least 50% seizure reduction in 20% or more of patients. Most adverse events were mild to moderate and reversible.

How the study worked

Systematic review searching MEDLINE, Cochrane Central Register, and trial registries through March 2024. All study types were eligible with no language or date restrictions. Risk of bias assessed using RoB2 and ROBINS-I V2. 14 of 722 identified records met inclusion criteria.

What this study cannot tell us

Included studies varied widely in design (RCTs, open-label, retrospective). No meta-analysis was performed due to heterogeneity. Most studies were relatively small. Long-term efficacy and developmental outcomes were not well captured. Publication bias may favor positive results.

How to read the evidence

Systematic review with comprehensive search and risk of bias assessment, though included studies were heterogeneous in design and no meta-analysis was performed.

When this study was published

Published 2025, searching literature through March 2024.

The bigger picture

CBD (as Epidiolex) is already approved for certain severe epilepsies, but this review broadens the evidence to the wider category of developmental and epileptic encephalopathies. The consistent findings across different study designs and populations strengthen the case for CBD as a treatment option in refractory pediatric epilepsy.

Questions still open

Whether long-term CBD use affects neurodevelopmental trajectories in these children
Which specific DEE subtypes respond best to CBD treatment

Common questions

What are developmental and epileptic encephalopathies?

These are severe genetic epilepsy conditions where frequent seizures and abnormal brain electrical activity contribute to developmental regression or delay. They typically begin in infancy or early childhood and are very difficult to treat with standard medications.

Did CBD completely stop seizures in these children?

Complete seizure freedom was not the typical outcome. The most common finding was a reduction in seizure frequency of 50% or more, which is still considered a meaningful clinical improvement for conditions this severe.

Read the original research

Efficacy and safety of cannabidiol in children with developmental and epileptic encephalopathies: A systematic review.

Seizure, 133, 114-127

View on PubMed ↗Publisher’s paper ↗

Citation

Saranti, Anna; Dragoumi, Pinelopi; Pavlogiannis, Konstantinos; Pavlou, Evangelos; Zafeiriou, Dimitrios. (2025). Efficacy and safety of cannabidiol in children with developmental and epileptic encephalopathies: A systematic review.. Seizure, 133, 114-127. https://doi.org/10.1016/j.seizure.2025.10.001