Parents of children with severe epilepsy have reported incredible recoveries when their children were given cannabidiol, a derivative of marijuana. The drug, a non-psychoactive compound that occurs naturally in cannabis, has been marketed with epithets like Charlotte’s Web and Haleigh’s Hope.
But those parents were taking a risk; there has been no clinical data on cannabidiol’s safety of efficacy as an anti-epileptic. This week, doctors are presenting the first studies trying to figure out if cannabidiol actually works. They say the studies’ results are promising, but with a grain of salt.
The largest study being presented at the American Epilepsy Society meeting in Philadelphia this week was started in 2014 with 313 children from 16 different epilepsy centers around the country. Over the course of the three-month trial, 16 percent of the participants withdrew because the cannabidiol was either ineffective or had adverse side-effects, says Dr. Orrin Devinsky, a neurologist at the New York University Langone Medical Center and lead author on the study.
But for the 261 patients that continued taking cannabidiol, the number of convulsive seizures, called grand mal or tonic-clonic seizures, went down by about half on average. Devinsky says that some children continued to experience benefits on cannabidiol after the trial ended. “In the subsequent periods, which are very encouraging, 9 percent of all patients and 13 percent of those with Dravet Syndrome epilepsy were seizure-free. Many have never been seizure-free before,” he says. It’s one of several [at least four. checking] papers on cannabidiol being presented this week at the American Epilepsy Society meeting in Philadelphia.
Marijuana Did Not Help All The Children With Severe Epilepsy
Twenty-five of those patients were followed for a yearlong study also presented at the meeting. Some of those patients did better, but one ended up doing worse. “A drug can induce an increase in seizures,” says Dr. Maria Roberta Cilio, a pediatric neurologist at UCSF Benioff Children’s Hospital who led that study. This happened with one of her patients. “For one particular child, the more the dose of [cannabidiol] was increasing, that increase was paralleled with an increase in seizure frequency,” she says.
Some patients in Devinsky’s trial also did worse while on cannabidiol, but he thinks there’s no way to tell if it was because of the drug or something else. He says we won’t know until a full clinical trial has run its course. Without that, the perceived effects of the drug might be a placebo effect or it could be some other confounding factor that hasn’t been caught in the study. What’s more, a few hundred patients isn’t a lot of patients, and doctors still need to see what will happen when a patient is on cannabidiol for more than a few months.
Epilepsy can be one of the most difficult syndromes to treat. About a third of patients have an intractable form of epilepsy. It’s common for children and adults with treatment-resistant epilepsy to exhaust the list of anti-seizure medications to little or no effect.
Devinsky says parents either have to purchase the cannabidiol from an artisanal distributor of hemp products or compound the drug themselves. Either way, “the consistency from batch to batch is quite uncertain,” he says.
And people sometimes try different formulations from several companies in the hope one will work. “As a practitioner, I have had families move to Colorado, and many tried multiple different products,” Devinsky says. That makes it really difficult to tell what is or isn’t working. “As a doctor, I often don’t feel like I know which of many factors is contributing to a patient doing better or worse. We absolutely need rigorous, scientific data on this,” he says.
Even though the results presented at the American Epilepsy Society meeting look encouraging, researchers caution that there’s no promise cannabidiol is really going to work for many of these treatment resistant epilepsy syndromes. Until there is a full clinical trial done with a placebo-controlled element, Devinsky and others say it’s impossible to tell if cannabidiol is having a real effect on epilepsy. That takes time and puts parents in a difficult position, he says. “Parents are desperate and they feel the medical community has failed them, which is true in many cases.”
Full on, randomized clinical trials testing cannabidiol for epilepsy are already underway, but it will still be some time until the results are out. Until then, Devinsky says, “Wait.”