A yearlong study involving more than 100 children with severe, drug-resistant epilepsy found that cannabidiol (CBD) was associated with sustained reductions in seizures, epilepsy severity, medication use and hospital visits.
The peer-reviewed study, published in the September issue of Epilepsy & Behavior, involved 103 patients under the age of 18 who received purified CBD through the Victorian Government’s Compassionate Access Scheme in Australia.
Researchers from the University of Melbourne, The Royal Children’s Hospital, Monash Medical Centre and Austin Health followed participants for up to 12 months.
All of the children had severe forms of epilepsy that had not adequately responded to available anti-seizure medications. Between November 2020 and May 2025, participants received high-purity CBD orally at doses ranging from 5 milligrams per kilogram of body weight per day to a maximum of 20 mg/kg/day.
CBD was initially added to patients’ existing medications, with other medications reduced over time when appropriate based on treatment response.
Researchers found that epilepsy severity declined significantly over the 12-month period. Among patients who remained on CBD for the full year, 77% showed some level of overall improvement, while 40% were rated as at least “much improved” on a clinical assessment scale.
Treatment was also associated with reductions in seizure frequency, use of other medications, episodes of status epilepticus, emergency department visits and hospitalizations.
Researchers said children who began the study with more severe epilepsy tended to experience somewhat greater reductions in symptoms. However, no particular type of epilepsy appeared substantially more likely to respond to CBD than others.
A significant portion of participants did not remain on treatment for the entire study. Overall, 46% discontinued CBD before reaching 12 months, primarily because it was not sufficiently effective. Thirty-one patients stopped due to lack of effectiveness, while seven discontinued because of adverse events.
Adverse events were reported in 31% of participants and were generally mild to moderate. About 6.8% of the patients discontinued treatment specifically because of side effects.
The researchers said the results provide evidence that CBD’s potential benefits for pediatric epilepsy may extend beyond Dravet syndrome and Lennox-Gastaut syndrome, conditions for which purified CBD is already used as a treatment.
Because the research was an open-label observational study without a placebo control group, it cannot establish that CBD directly caused the improvements. The researchers said additional studies are needed to determine which patients are most likely to benefit from treatment.
The study was funded by the Victorian Department of Health.
