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 Journal of Neurology, Neurosurgery and Psychiatry, 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.
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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.
Emily Stockings, PhD, 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.