In a new study conducted by researchers from 19 universities and research hospitals in Italy, highly purified CBD reduced seizures in two-thirds of patients with Rett Syndrome (RTT) or CDKL5 Deficiency Disorder (CDD), two rare genetic conditions often marked by severe drug-resistant epilepsy.
Published in the journal Epilepsia Open, the study involved 27 patients—26 of them female—with genetically confirmed RTT or CDD who received Epidiolex, a pharmaceutical-grade CBD extract, alongside their existing antiseizure medications.
Participants ranged in age from about 8 to 18 years and were treated for a median duration of 14 months. The CBD dosage was gradually increased from 5 mg/kg/day to as high as 20 mg/kg/day, tailored to each patient’s response and tolerance.
In the study, 66.6% of participants experienced a reduction in seizure frequency compared to baseline. Of those, nearly 26% saw their seizures drop by more than 75%, and 41% had reductions of more than 50%.
Adverse effects were mostly mild and included somnolence (11%), irritability or agitation (7%), loss of appetite (7%), and insomnia (4%). No serious adverse events were reported. Importantly, caregivers of nearly half the participants said they noticed improvements in attention and responsiveness, with others reporting better sleep and enhanced motor function.
The benefits appeared to be independent of whether the underlying genetic mutation was in MECP2 (linked to RTT) or CDKL5, suggesting that CBD may hold therapeutic potential across different forms of genetic epilepsy.
Researchers conclude the study by stating:
CBD resulted effective in reducing seizure frequency in 66.6% of the study sample, regardless of the pathogenic variant; side effects were mild, and caregivers reported an improvement in behavioral and motor features.
