Effectiveness and tolerability of cannabidiol in paediatric epilepsy: a one-year multisite prospective study.

Epilepsy affects approximately 50 million people worldwide, with drug-resistant forms occurring in over a third of cases and resulting in major health and quality-of-life burdens. Cannabidiol, a non-psychoactive cannabis compound, shows promise in paediatric epilepsy, but evidence remains limited for its use. This multi-site open-label observational study in Australia involved 103 paediatric epilepsy patients receiving purified cannabidiol via a compassionate access scheme. Clinicians provided data at baseline, three and twelve months, including seizure frequency, hospitalisations, medication use and adverse events. Epilepsy severity was assessed using the Global Assessment of Severity of Epilepsy instrument and overall improvement was measured with the Clinical Global Impression Improvement (CGI-I) scale. A total of 46% of patients who commenced treatment discontinued before twelve months, mainly due to lack of effectiveness (n = 31) and adverse events (n = 7). Among those continuing, 40% were rated at least "much improved" on the CGI-I scale at 12 months with sustained reductions in epilepsy severity, seizures, medication use, status epilepticus, emergency visits and hospitalisations. Adverse events were reported by 31%, mostly mild to moderate. In conclusion, cannabidiol treatment was associated with sustained improvements across multiple measures; however, frequent discontinuations highlight the need for further research to better identify patients most likely to respond.