More on Epilepsy and Marijuana

November 5, 2014 · Epilepsy News

iStock_000034048212_SmallOn May 29, 2014 Minnesota became the 22nd state, in addition to the District of Columbia, to enact laws legalizing the use of medical marijuana. Nine specific medical conditions have been identified for legal use of medical marijuana in Minnesota, including those with seizures/epilepsy. Minnesota’s law has been perceived as more restrictive than other states, as it mandates that delivery can only be by pills, consumption or oils, or vaporization (similar to an e-cigarette). Smoking of leaf marijuana remains illegal in all circumstances in the state of Minnesota. Home cultivation of marijuana is also not allowed. Patients will need an ID card certifying that they have a qualifying diagnosis, and must pay an annual fee to participate in the program. Two manufacturers are to be approved in the near future, and all dispensed marijuana products can only be picked up at a handful of sites around the state, with those locations still to be determined. Minnesota will not recognize ID cards from other states. The expectation is that the state will be ready for product dispensing on July 1, 2015.

The potential benefit of medical marijuana has been a hot topic in the press based upon anecdotal reports of improved seizure control using marijuana products. Patients are now asking, “Would medical marijuana benefit the treatment of my epilepsy?”

As with all treatments of seizures and epilepsy, our recommendations as physicians are guided by evidence based medicine; research that has been done that specifically looks at whether a treatment is beneficial in terms of seizure control, and also looking at potential side effects or problems that may arise from use of a new medication. Unfortunately, there has not been significant research yet done with marijuana looking at these questions in patients with epilepsy.

The two major components of marijuana that have effects on the brain are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC has the psychotropic effects or “high” that is associated with marijuana use. There has been great interest in varieties of marijuana that are high in CBD and low in THC, or in isolation of CBD oils in medicinal use to avoid the psychotropic effects. Unfortunately, the amount of data looking at CBD in the treatment of epilepsy is scant.

A recent review in which they scoured the medical literature for randomized studies found that only 4 studies had been published, with a total of 48 patients (1). Little information about seizure control was provided in these studies, and the authors summarized that based on review of the literature, there was no ability to provide any conclusion about the benefits of cannabinoids in epilepsy.

Similarly, the a report of a Guideline Subcommittee of the American Academy of Neurology published an article looking at the effectiveness and safety of medical marijuana in different neurological conditions(2). They found evidence to support the use in such things as spasticity associated with Multiple Sclerosis, but in terms of epilepsy, “oral cannabinoids are of unknown efficacy (effectiveness)”.

A large, national medical group, the American Epilepsy Society also released a position statement that included the following (3):

“The recent anecdotal reports of positive effects of the marijuana derivative cannabidiol for some individuals with treatment-resistant epilepsy give us reason for hope. However, we must remember that these are only anecdotal reports, and robust scientific evidence for the use of marijuana is lacking”.

“At present, the epilepsy community does not know if marijuana is safe and effective nor do we know the long-term effects that marijuana will have on learning, memory, and behavior, especially in infants and young children. This knowledge-gap is of particular concern because both clinical data in adolescents and adults and laboratory data in animals demonstrate that there are potential negative effects of marijuana on these critical brain functions”.

In summary, there is intrigue as to whether medical marijuana, and in particular CBD is an effective and safe treatment for epilepsy. At this time, there is not enough evidence to support its use. What everyone can agree on is that we need new and more effective treatments for patients with epilepsy who continue to have seizures despite current use of medications to stop seizures. To that end, we need randomized controlled trials to be performed to answer the question of whether CBD is an efficacious and safe treatment for epilepsy.


1. Gloss, D. and Vickrey B. Cannabinoids for epilepsy. Cochrane Database Syst. Rev. 2012. 6:CD009270

2. Koppel et al. Systemic review: Efficacy and safety of medical marijuana in selected neurologic disorders. 2014: 82, 1556-1563.

3. AES position on medical marijuana. Updated February 2014.

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