Epilepsy is a common neurological disorder, affecting about 3.4 million people in the U.S. The seizure disorder is a spectrum condition, meaning it comes in many different types and levels of severity, and some forms are resistant to traditional medications, so patients have looked for alternative therapies over the years, including cannabidiol, (CBD), a non-psychoactive compound in cannabis. Interest in CBD as an epilepsy treatment grew following media reports that it helped in children with a severe form of the disease. Since that time, several studies have shown that CBD significantly reduced the frequency of certain seizures, and the U.S. Food and Drug Administration (FDA) has approved Epidiolex, a CBD oral solution, to treat rare, severe forms of the disease. The FDA noted there were “adequate and well-controlled clinical studies that supported the approval.” The Epilepsy Foundation said on its website that research on CBD has been hard to do because of federal regulations and limited access to the substance, but recently, well-qualified studies have shown that CBD could benefit people who haven’t responded to traditional therapies. Epidiolex is giving some of the most vulnerable patients new hope, the Foundation said, while also advocating for further research into the benefits of CBD for epilepsy and seizure disorders. Meanwhile, the results of a preliminary Israeli study presented in late 2018 noted the benefits of CBD may fade over time, with some patients developing tolerance. The cannabis derivative may not be a magic bullet, but it could represent a promising treatment alternative for certain patients.

Girl with EEG electrodes attached to her head iStock / luaeva

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What Is Epilepsy?

The hallmark of epilepsy is recurrent, unprovoked seizures, which differs from seizures brought on by other factors, such as a drug overdose or low blood sugar. The cause of the seizures in epilepsy is often unknown, though they may be hereditary or brought on by a brain injury. Treatment includes medications and may also include diet changes, neurostimulation, which involves using a device to send electrical currents to the nervous system, and surgery to remove the part of the brain causing the seizures, the Epilepsy Foundation noted. These options aren’t for everyone — some people may not tolerate the medicines or be poor candidates for surgery, and this is where alternative and complementary treatments come in to play. According to a 2015 review of the literature published in Neurotherapeutics, cannabis has been used to treat seizures for thousands of years. The review noted that CBD is the main cannabis component linked to reducing seizures — it avoids the psychoactive, or “high,” effects of the body’s endocannabinoid system “to provide a well-tolerated, promising therapeutic for the treatment of seizures…”

The Gold Standard Trials

Two studies on CBD published in the New England Journal of Medicine were randomized, double-blind, placebo-controlled trials, which are considered the gold standard in research. Both found that CBD had significant benefits for epilepsy patients over a placebo. The first study focused on patients with Dravet syndrome, a severe form of epilepsy characterized by frequent and prolonged seizures, while the second looked at patients with Lennox-Gastaut Syndrome, (LGS), a severe form of epilepsy in children characterized by different types of seizures. In the first study, published in 2017, 120 children and young adults with Dravet syndrome and drug-resistant seizures were randomly assigned to receive either CBD or a placebo. The study measured the change in the number of convulsive seizures over the treatment period. The percent of people who experienced at least a 50 percent reduction in how often they had convulsive seizures was 43 percent with CBD compared to 27 percent with a placebo. There was no significant reduction, however, with non-convulsive seizures.

Magnetic resonance scan of the brain with skull. MRI head scan on dark background. X-ray medicine and medication concept iStock / Ildar Imashev
There were some side effects noted in the CBD group that the placebo group didn’t experience, including diarrhea, vomiting, fatigue, fever and abnormal results on liver-functioning tests. In the second study, published in 2018, people with LGS who had two or more drop seizures each week during an evaluation period were given different doses of CBD or a placebo. During the treatment period, drop seizures decreased by 42 percent in the highest-dose category and decreased 17 percent in the placebo group. These patients also experienced some side effects, including sleepiness and diarrhea.

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Drugs Often Lose Effectiveness Over Time

The preliminary Israeli study found that one-third of participants developed tolerance to CBD that lowered its effectiveness after about seven months. The news isn’t surprising - it’s common for patients to develop tolerance to antidepressants, opioids, and other drugs. In the case of antidepressants, doctors aren’t certain about the cause behind the “poop-out effect,” or why it happens in some people and not others, and in the case of opioids, a 2012 study demonstrated how neural cells build up resistance to opioid pain drugs in a matter of hours. At this point, CBD represents a promising treatment for epileptic seizures, though researchers are still calling for additional studies to monitor its effects long-term. Both the Epilepsy Foundation and the American Epilepsy society offer further resources for people seeking to join clinical trials, and information on other treatments that may be currently available.