A new study examines the effectiveness of a cannabis derivative in treating a rare but severe form of epilepsy.

The anticonvulsant properties of cannabidiol have been previously documented, but this is the first time that the compound was tested in a large-scale, double-blind, randomized clinical trial.

Researchers from New York University (NYU) – led by Dr. Orrin Devinsky, professor of neurology, neurosurgery, and psychiatry, as well as director of the Comprehensive Epilepsy Center at NYU Langone Medical Center – set out to examine the effects of cannabidiol (CBD) on Dravet syndrome.

Dravet syndrome is a rare but severe form of epilepsy that usually occurs in a child’s first year of life and often develops into intractable epilepsy later in life.

CBD is a cannabis derivative that does not have psychoactive properties in the same way that tetrahydrocannabinol (THC) does.

The new study, published in the New England Journal of Medicine, examines a pharmaceutical version of CBD that has not yet been approved by the Food and Drug Administration (FDA).

The anticonvulsant properties of CBD, as well as its potential for treating epilepsy, have been documented before in both preclinical and clinical studies.

The evidence available seems to indicate that CBD can help to treat epilepsy in both children and adults with refractory epilepsy.

Devinsky himself also led a previous open-label intervention in December 2015 to assess the effects of CBD on Dravet syndrome and other forms of treatment-resistant epilepsy.

Although the results were promising then, both the researchers and the study participants’ families knew that they were administering and receiving the treatment, which may have influenced the results.

This new trial, therefore, aimed to eliminate the possibility of this kind of bias by blinding both the researchers and the patients to the fact that they were participating in a trial.

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Studying the effects of CBD

Devinsky and his team examined the effect of CBD on 120 children and teenagers with Dravet syndrome.

Participants were between 2 and 18 years of age.

As part of this clinical trial, participants were divided into random groups in 23 medical sites across the United States and Europe.

They were administered either 20 milligrams of CBD per kilogram, or a placebo.

The intervention was added to the participants’ existing treatment over the course of 14 weeks.

During this time, the patients’ seizure frequency was monitored. The seizures were also monitored for a month prior to the study, so that researchers had an understanding of the patients’ condition at baseline.

CBD significantly lowered the frequency of the seizures in the group that received the treatment.

CBD-treated patients had 39 percent fewer seizures as a result of the intervention.

This amounts to a drop in the median number of monthly seizures from almost 12 to approximately six. For three of the patients, seizures completely stopped.

In the placebo group, the seizures dropped by 13 percent, from 15 seizures per month to 14.

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Mild to moderate side effects

The CBD treatment did come with side effects, although the patients reported these as being mild or moderate.

Those included vomiting, fever, and fatigue.

They were experienced by 93 percent of the CBD patients. In the placebo group, 74 percent of the participants had side effects.

In the CBD group, eight patients had to drop out from the trial due to the adverse effects of the treatment, compared with one patient in the placebo group.

In the future, researchers plan to look at ways of improving the safety of the CBD treatment and diminishing its side effects. They also plan to examine whether or not CBD is still effective if taken in smaller doses.

"Cannabidiol should not be viewed as a panacea for epilepsy, but for patients with especially severe forms who have not responded to numerous medications, these results provide hope that we may soon have another treatment option,” said Devinksy. “We still need more research, but this new trial provides more evidence than we have ever had of cannabidiol's effectiveness as a medication for treatment-resistant epilepsy."