A study published today in Clinical Therapeutics found that cannabis-based products were associated with substantial seizure reductions among patients with refractory epilepsy treated through Brazil’s public health system.
The study was conducted by researchers from Universidade Federal de Minas Gerais, the Brazilian Health Regulatory Agency and Université de Bordeaux. It examined 91 patients enrolled in the Canabidiol–SUS Project, a public health program in Brazil’s Federal District that provides access to cannabis-based products for patients with severe forms of epilepsy.
According to the study, “Cannabis-based products have emerged as a potential therapeutic option for refractory epilepsy; however, real-world evidence remains limited, particularly within public health systems.” Researchers said they aimed to evaluate both the effectiveness and safety of the products, while also identifying factors linked to perceived treatment success.
Overall, 70.3% of patients reported at least a 50% reduction in seizure frequency after using cannabis-based products. The rate was considerably higher among current users, with 94.7% reporting a reduction of at least 50%, compared with 57.1% among those who had stopped treatment.
Patients who used cannabis-based products for more than 12 months were significantly more likely to report improvement, with researchers finding that treatment duration beyond one year was associated with higher perceived effectiveness. In the multivariate analysis, use for more than 12 months was linked to an odds ratio of 23.79 for perceived effectiveness.
Access barriers appeared to play a major role in treatment outcomes. Among those who stopped treatment, the most common reason was difficulty accessing the products. Researchers found that discontinuation due to access issues was negatively associated with effectiveness, with an odds ratio of 0.074.
“Patients receiving cannabis-based products frequently reported substantial seizure reduction and an acceptable safety profile in this real-world public health setting,” the researchers wrote. “However, interpretation should consider the cross-sectional design, self-reported outcomes, and heterogeneity of products.”
The study included patients registered for cannabis-based treatment between 2017 and 2022, with interviews conducted between October 2023 and February 2024. Most participants were children or adolescents, and 89% of interviews were completed by caregivers or legal guardians.
CBD isolate products were the most commonly used, accounting for 73.6% of cases, while 18.7% used CBD products that included other cannabinoids. Most products were industrialized formulations.
Adverse events were reported by 51.6% of participants, most commonly sleep disturbances, mood changes and gastrointestinal symptoms. Sleep disturbances were reported by 28.6% of patients, mood, psychiatric or neurological changes by 24.2%, and gastrointestinal symptoms by 19.8%. Four patients, or 4.4%, reported an increase in seizure frequency.
Researchers said the safety profile was generally acceptable, though they emphasized the need for clinical monitoring, pharmacovigilance and better product standardization.
In their conclusion, the researchers said “high perceived effectiveness of cannabis-based products was observed among patients with refractory epilepsy treated within the public health system of the Federal District, Brazil,” with at least a 50% seizure reduction reported by 70.3% of patients.
They added that administrative and financial barriers were linked to treatment interruption and poorer perceived outcomes, “highlighting the importance of continuous and equitable access to therapy.”
