Promising results from a large-scale, controlled, Phase 3 clinical study of epilepsy patients being treated with cannabidiol (CBD) found that almost 40 percent of people with Lennox-Gastaut syndrome (LGS) had at least a 50 percent reduction in drop seizures, compared to 15 percent taking a placebo. LGS is a severe form of epilepsy that often results in impaired intellectual development and does not usually respond well to medications. The study involved 225 people, who for 14 weeks received either a daily higher dose of cannabidiol, a lower dose, or a placebo in addition to their current medications. The average age of participants was 16, and prior to the study all had an average of 85 drop seizures per month. On average, participants had already tried six epilepsy drugs that were not successful, and continued to take about three epilepsy drugs during the study.
Those taking the higher 20 mg/kg daily cannabidiol dose saw an overall 42 percent decrease in drop seizures. For 40 percent of the participants, seizures were reduced by 50 percent or more. Comparatively, the placebo group experienced a 17 percent decrease in drop seizures, and seizures were cut in half or more for 15 percent of the participants. Participants receiving the CBD were more likely to report an improvement in overall condition, with 66 percent saying they had improved, compared to 44 percent of patients in the placebo group.