Cannabidiol (CBD) is safe and effective in patients with highly drug-resistant epilepsies, including Dravet syndrome and Lennox-Gastaut syndrome (LGS), according to a monocentric real-world study published in the journal Seizure. The study showed that CBD led to a dramatic reduction in seizure frequency in more than 25% of patients.

The authors of the study concluded that CBD is a safe and effective therapeutic option for these patients.

Their aim was to evaluate the safety and efficacy of CBD to treat epilepsy in a real-world setting. They analyzed 42 patients with epilepsy, aged 25 to 47 years, who were treated with CBD between March 1, 2019, and November 30, 2022. Of these, 18 had LGS and 5 had Dravet syndrome.

CBD was prescribed on-label for another patient who had tuberous sclerosis. The remaining 18 patients, who were prescribed CBD off-label, had ring chromosome 20 or ring chromosome 17 syndrome, Lafora disease, Unverricht-Lundborg disease, polymicrogyria, febrile infection-related epilepsy syndrome, nonlesional focal epilepsy, or developmental and/or epileptic encephalopathy of unknown etiology. 

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Patients were followed up for at least 3 months and were evaluated at baseline and at 3, 6, and 12 months post-treatment. 

When they experienced a reduction in seizures of more than 30% but less than 80% compared to baseline, participants were classified as responders. If they showed a reduction of 80% or more compared to baseline, participants were classified as super responders. 

Researchers also recorded the occurrence of adverse events.

The results showed that 3 months after CBD treatment 10 patients (23% of all patients) were responders while 12 (29% of all patients) were super-responders. The efficacy of the treatment was sustained at 6 and 12 months. 

Around half (52.3%) of patients developed adverse events following treatment. The most common of these were drowsiness affecting 36.5% of them and diarrhea affecting 9.8%. 

The retention rate was 85.7% at 3 months, 78.6% at 6 months, and 71.4% at 12 months. 

“CBD [is] a safe and effective therapeutic option for highly drug-resistant patients, leading to a dramatic reduction in seizure frequency in over one-fourth of them, including off-label indications,” the researchers said. 


Walter V, Lorenzo M, Federica P, et al. Real-world experience with cannabidiol as add-on treatment in drug-resistant epilepsy. Seizure. 2023;17;111:39-41. doi:10.1016/j.seizure.2023.07.009