CBD Reduced Seizures by Half or More in Over 50% of Children With Drug-Resistant Epilepsy | Research

The takeaway

Among 551 children with treatment-resistant epilepsy across 10 centers, purified CBD reduced seizures by 50% or more in half of patients, with 14% becoming seizure-free.

Parents of children with drug-resistant epilepsy, pediatric neurologists, epilepsy researchers.

50.6% achieved 50%+ seizure reduction

What the researchers found

In 551 children with drug-resistant developmental and epileptic encephalopathies treated with purified CBD at 10 centers, 50.6% achieved at least 50% seizure reduction after 12-32 months, including 14.2% who became seizure-free. Long-term follow-up of a subset (280 patients, 24-32 months) showed sustained efficacy with 51.4% maintaining at least 50% reduction and 10.2% remaining seizure-free. The treatment was safe and well-tolerated.

Why it matters

This is one of the largest real-world CBD epilepsy studies to date. The finding that purified CBD helps approximately half of children with the most treatment-resistant forms of epilepsy, including rare genetic conditions, confirms and extends findings from earlier clinical trials into everyday clinical practice.

The numbers in context

551 patients enrolled. Mean age at CBD start: 8.5 years. 50.6% achieved >50% seizure reduction. 14.2% became seizure-free. 280 patients at long-term follow-up: 51.4% maintained >50% reduction, 10.2% seizure-free. Median follow-up: 22 months. 10 centers.

How the study worked

Descriptive real-world multicenter study of children aged 0.5-16 years with ILAE-defined drug-resistant developmental and epileptic encephalopathies treated with purified CBD at 10 centers (March 2021-December 2024). Etiologies: structural (45%), genetic (28.8%), immune (0.9%), infectious (0.5%), unknown (24.3%). Median follow-up: 22 months.

What this study cannot tell us

Observational design without placebo control. Concomitant antiepileptic medications make isolating CBD effects difficult. Selection bias: centers may preferentially treat and report patients they expect to respond. Loss to follow-up could bias long-term results.

How to read the evidence

Strong: large multicenter real-world study (N=551) with long follow-up, though observational design limits causal conclusions.

When this study was published

2025 study (data from 2021-2024)

The bigger picture

Purified CBD (Epidiolex) was initially approved for specific epilepsy syndromes, but this real-world study shows effectiveness across diverse etiologies. The sustained response at 2+ years and the tolerability profile support CBD as a long-term treatment option for the most challenging pediatric epilepsy cases.

Questions still open

Can predictive markers identify which patients will respond best to CBD? What is the optimal CBD dose across different etiologies? Would earlier CBD introduction improve response rates?

Common questions

Does CBD work for children's epilepsy?

In this study of 551 children with the most treatment-resistant forms of epilepsy, purified CBD reduced seizures by 50% or more in about half of patients, with 14% becoming completely seizure-free.

Does CBD continue to work long-term for epilepsy?

Yes. After 2+ years of follow-up, about half of patients maintained significant seizure reduction and 10% remained seizure-free, showing sustained effectiveness.

Read the original research

A multicenter study on the use of purified cannabidiol for children with treatment-resistant developmental and epileptic encephalopathies.

Epilepsy & behavior : E&B, 171, 110590

View on PubMed ↗Publisher’s paper ↗

Citation

Reyes Valenzuela, Gabriela; Espeche, Alberto; Fortini, Sebastian; Gamboni, Beatriz; Adi, Javier; Semprino, Marco; Fasulo, Lorena; Galicchio, Santiago; Cachia, Pedro; Chacón, Santiago; Calvo, Agustin; Beltran, Lucas; Bautista, Claudia; Caraballo, Roberto H. (2025). A multicenter study on the use of purified cannabidiol for children with treatment-resistant developmental and epileptic encephalopathies.. Epilepsy & behavior : E&B, 171, 110590. https://doi.org/10.1016/j.yebeh.2025.110590