A new real-world study involving over 550 children with severe epilepsy found that purified cannabidiol (CBD) significantly reduced seizure frequency in more than half of patients, including some who became seizure-free.

The study is being published in the October 2025 issue of the journal Epilepsy & Behavior, and it was published online of ahead of print by the U.S. National Library of Medicine.

Researchers evaluated CBD’s safety and efficacy as an add-on treatment for children with developmental and epileptic encephalopathies (DEE) across 10 medical centers. Participants ranged from 6 months to 16 years old and were followed for a median of 22 months.

At the end of the study period, 50.6% of patients saw their seizure frequency cut by at least half, and 14.2% were seizure-free. Only 6.2% saw no change. Adverse effects occurred in roughly a third of patients but were typically mild and resolved with dosage adjustments. Most children continued using CBD through the end of the study.

Importantly, the study also included infants under one year old, offering evidence that early treatment initiation may help reduce the neurological toll of seizures during a critical developmental window. Researchers concluded that CBD is a safe and effective treatment for drug-resistant epilepsy in children with various underlying causes.