Room for Debate: Can Cannabis Curb Seizures?

A series of articles published in the journal Epilepsia are fueling the debate about the use of medical marijuana and pure Cannabidiol (CBD), an active substance in the cannabis plant, to treat neurological conditions.

Some clinicians say it's safe, while others claim more testing is needed—and then, of course, is the fact that not all states have legalized its use. Currently, medical marijuana is legal in 21 states along with Washington, D.C.

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Case Study Shows Efficacy

In one article, Dr. Edward Maa, chief of the Comprehensive Epilepsy Program at Denver Health in Denver, Colo., discusses giving medical marijuana to a child with Dravet syndrome, a severe form of epilepsy. The patient took Charlotte's Web, which is comprised of a strain of cannabis high in CBD and low in tetrahydrocannabinol (THC), along with the regular antiepileptic drug regimen. The child's seizure frequency was lowered from 50 convulsions per day to two or three nighttime convulsions per month.

"Colorado is 'ground zero' of the medical marijuana debate," says Maa. "As medical professionals, it is important that we further the evidence of whether CBD in cannabis is an effective antiepileptic therapy."

Dr. Carl W. Bazil, a professor of clinical neurology and director of the Division of Comprehensive Epilepsy Center and Sleep Center at Columbia University in New York, knows there are many anecdotal reports of cannabis aiding people with epilepsy, but says the studies don't prove it. 

"Individuals who think that cannabis improved or cured their seizures could have improved for other reasons," he says.

According to the National Institute on Drug Abuse (NIDA), the Food and Drug Administration (FDA) has approved dronabinol (Marinol), which contains THC and is used to treat nausea caused by chemotherapy as well as wasting disease caused by AIDS. It has also approved nabilone (Cesamet), which is made of a synthetic cannabinoid similar to THC and is used to treat the same conditions. Another drug, Sativex, is being used in the United Kingdom to treat multiple sclerosis and it is now in Phase III clinical trials in the U.S. for cancer pain.

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More Information Needed

Another journal article discusses scientific evidence of CBD being used to treat epilepsy and other neurological or psychiatric disorders such as anxiety, schizophrenia, and addiction. Previous studies found that THC, the primary psychoactive substance in cannabis, and CBD, the main non-psychoactive ingredient, display anticonvulsive properties in animals. But data presented in the research is limited for chronic episodes—and missing entirely for human cases. Other studies say medical marijuana with high ratios of CBD and THC are more useful at controlling seizures, but that data wasn't well controlled, according to some. 

"While cannabis has been used to treat epilepsy for centuries, data from double-blind randomized, controlled trials of CBD or THC in epilepsy is lacking," says Dr. Orrin Devinsky, director of the Comprehensive Epilepsy Center at NYU Langone Medical Center in New York and Saint Barnabas Medical Center in New Jersey. "Randomized controlled studies of CBD in targeted epilepsy groups, such as patients with Dravet or Lennox-Gastaut syndromes, are in the planning stages."

Dr. Maria Roberta Cilio, who heads up research in pediatric epilepsy at the University of California, San Francisco (UCSF) Epilepsy Center, says it's too soon to conclude whether the use of medical marijuana for these conditions is safe or effective. She wants to see more studies.

"There is a critical need for new therapies, especially for childhood-onset treatment-resistant epilepsies that impair quality of life and contribute to learning and behavioral disorders," she says.

Learn More: What Causes Seizures? »

Obstacles to Research

Dr. Gary Mathern, a professor of neurosurgery at University of California, Los Angeles (UCLA) and a co-editor for Epilepsia, says the articles show that the evidence for the use of medical marijuana is "circumstantial and unscientific."

"There is insufficient quality data that shows safety, especially in children and for long term use, and whether it works," Mathern says. "Getting interpretable data is hindered because there are no pharmacological grade compounds of pure THC or CBD to use in patients for testing secondary to legal restrictions at the federal level in the U.S. Hence, there is no genuine data on which to form an opinion on using this for children."

He adds that there is little Class I data on the use of most of anti-seizure medications used on children under age 12 years; that data wasn't necessary for pharmaceutical companies to obtain FDA approval.

According to Bazil, studying cannabis is difficult because many active compounds could help or harm patients, and there is no way to measure the dosage. He concurs that the FDA classification of schedule I (with no accepted medical use) makes obtaining it for good clinical trials extremely difficult.

Mathern is asking for patients, medical professionals, and clinicians to provide feedback on the issue via a survey.

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