A reasonable number of patients with treatment-resistant epilepsy experienced a decrease in the frequency of seizures when treated with pharmaceutical-grade cannabidiol, according to findings from a systematic review.
The review, published online March 6 in the, centers on 36 studies testing the use of cannabinoids as adjunctive treatments for treatment-resistant epilepsy, including six randomized controlled trials involving a total of 555 patients and 30 observational studies involving 2,865 patients.
Two randomized, controlled trials representing a total of 291 patients (one with 120 patients with Dravet syndrome and another with 171 patients with Lennox-Gastaut syndrome) found cannabidiol (CBD) treatment was 74% more likely than placebo to achieve a greater than 50% reduction in seizures. In the observational studies, nearly half (48.5%) of the 970 patients across a range of epilepsy subtypes achieved a 50% or greater reduction in seizures.
, of the National Drug and Alcohol Research Centre at the University of New South Wales, Sydney, and her coauthors estimated that eight patients would need to receive CBD treatment to achieve a 50% reduction in seizures in one person. However, they also pointed out that the quality of the evidence was mixed.