cbd for epilepsy

CBD Oil For Epilepsy: Does Science Show Positive Treatment Results?

The effect of Cannabis sativa and its compounds on epilepsy is one of the most widely studied and accepted therapeutic roles of phytocannabinoids.

Even with current medical interventions, 30% of epilepsy patients have treatment-resistant epilepsy and do not respond well to treatment, with some people experiencing little to no reduction of their symptoms, several side effects, or both.

In numerous states, Cannabis sativa or its compounds, such as cannabidiol (CBD), have been approved for the treatment of epilepsy.

In this article, we will set out to answer the question: does CBD oil help those with epilepsy? We will review what the scientific literature has found regarding the efficacy of CBD for epilepsy, the side effects experienced, and the ways in which CBD oil works.

Epilepsy Overview

Epilepsy is a neurological condition characterized by recurrent seizures. There are many types of epilepsy, with treatments including steroids, antiepileptic drugs, and surgery. (3)


Even for the 70% of epilepsy patients that respond to current therapies, the side effects of the drugs and other therapies can be disabling. It has been found that epilepsy patients often suffer from sleep deprivation, excess alcohol consumption, and breakthrough seizures. This reduction in the quality of life for epilepsy patients is of paramount concern. (4)

While any form of epilepsy can be treatment resistant, there are certain conditions that are more frequently resistant to medical therapies: Dravet Syndrome (DS), Lennox-Gastaut Syndrome (LGS), Febrile Infection-Related Epilepsy Syndrome (FIRES), and Tuberous Sclerosis Complex (TSC).

An additional hurdle to treatment is that many epilepsy patients are young children, with treatment-resistant epilepsy in the first years of life being tied to high rates of delays in behavior, motor, and cognitive functions.

It is for these reasons that researchers are searching for a way to help those suffering from epilepsy, and CBD products are at the forefront of this research.

Cannabis Sativa and Cannabidiol for Epilepsy

Cannabis has been used for thousands of years for the treatment of epilepsy, with the last few years heralding numerous placebo-controlled, randomized trials for CBD in the treatment of epilepsy. (4)

Cannabidiol, also known as CBD or hemp oil, is a non-psychoactive cannabinoid found in the Cannabis sativa plant. Unlike THC, CBD does not leave those who take it feeling “high.” While there are over 85 cannabinoids found in cannabis plants, THC and CBD are the most abundant and thoroughly studied.

Numerous preclinical studies on animals have found CBD to exhibit anti-convulsant effects. (5,6) Here we will review many of the human studies that have been conducted in relation to CBD oil and epilepsy.

Cannabidiol Helps Reduce Seizures in Patients with Treatment-Resistant Epilepsy (TRE)

In a 2016 study published in The Lancet Neurology, 162 patients between 1 and 30 years of age who had childhood onset, severe, intractable, treatment-resistant epilepsy were treated with oral CBD (in addition to their antiepileptic drugs) daily for 12 weeks. (2)

CBD dosage started at 2-5 mg/kg body weight/day and was slowly increased up to an intolerance or a maximum of 25 mg/kg/day or 50 mg/kg/day, depending on the study site.

The researchers found a 36.5% average reduction in monthly motor seizures following the 12 weeks of CBD treatment. They concluded that cannabidiol may reduce the frequency of seizures for young adults and children with TRE. CBD side effects were reported to be adequate, with mostly mild side effects observed.

Of these side effects, one of the most common had to do with the interaction of CBD with the antiepileptic drug (AED) Clobazam. In the study, 85 participants were taking Clobazam, with 51% of these patients experiencing fatigue or somnolence, in comparison to 21% of the patients who were treated with a different AED.

This study was not a placebo-controlled study, thus further studies need to be conducted to rule out any placebo effect.

State-Sponsored Study finds CBD to Reduce Seizure Frequency

In a 2016 study published in Neurology, researchers treated patients who had TRE with Epidiolex, a pure plant-derived liquid formulation of cannabidiol, for six months.

23 children and 28 adults took part in the study. CBD dosage started at 5 mg/kg/day and was increased biweekly by 5 mg/kg/day up to tolerance or a maximum of 25 mg/kg/day. Seizure frequency was measured three months prior to CBD treatment and for 6 months during CBD treatment.

The researchers found a significant reduction in seizure frequency following 6-months of CBD treatment for both pediatric and adult epilepsy patients, with 49% of patients experiencing greater than or equal to a 50% reduction in seizure occurrence. 7 participants quit the study early due to lack of efficacy and 2 participants quit due to diarrhea side effects. 2 patients were seizure free at the last assessment.

Randomized Placebo-Controlled Studies Show CBD to Reduce Seizures

In 2016, GW Pharmaceuticals announced positive results from three studies on the effect of Epidiolex (CBD) on epilepsy, with a fourth study underway. (4,8)

For patients with Dravet Syndrome (DS) and Lennox-Gastaut Syndrome (LGS), 20 mg/kg/day of Epidiolex was compared to placebo. Additionally, a dose-finding study comparing Epidiolex 10 mg/kg/day, 20 mg/kg/day, and placebo on LGS patients was conducted.

Preliminary results were announced, with future publications in peer-reviewed journals underway.

For the study with DS patients, 120 patients who were not responding well to AEDs were split into either a 20 mg/kg/day Epidiolex treatment or placebo. Baseline seizure frequency was found to be a median of 13 seizures per month.

Following 14 weeks of treatment, the median reduction in seizure frequency was 39% in the Epidiolex group compared to 13% in the placebo group, with the difference between the groups significant.

In this study, 84% of the side effects reported were mild to moderate, although there were 10 more severe side effects reported, with 8 of 10 belonging to the Epidiolex group.

Side effects reported were diarrhea, fatigue, somnolence, decreased appetite, vomiting, upper respiratory tract infection, pyrexia, and convulsion.

Similar results and side effects were found in the study of Epidiolex versus placebo for those with LGS. (4,9) 171 patients were randomized into either 10 mg/kg/day or placebo group for 12 weeks. Those in the CBD group experienced a 44% reduction in seizure frequency compared to 22% in the placebo group.

86% of participants in the CBD group reported side effects, and 69% in the placebo group reported side effects. Of those in the CBD group, 78% were mild to moderate, with 23% of the CBD group participants reporting serious adverse events.

Lastly, in the dose-ranging study on patients with LGS, patients were split into either 20 mg/kg/day epidiolex, 10 mg/kg/day Epidiolex, or placebo. The reduction in seizure frequency was 17% in the placebo group, 37% in the 10 mg/kg/day Epidiolex group, and 42% in the 20 mg/kg/day Epidiolex group, showing slightly higher efficacy at 20 mg/kg/day CBD when compared to 10 mg/kg/day CBD.

Results are pending for the placebo-controlled trial of Epidiolex for those with Tuberous Sclerosis Complex (TSC).

The results of these Phase 3 clinical trials were such that the FDA granted Epidiolex with Fast Track and Orphan Drug Designations for DS, LGS, and TSC.

How CBD Works for Epilepsy

While the exact mechanisms for how CBD reduces seizures isn’t known for certain, researchers have found possible explanations. 

Phytocannabinoids, such as THC and CBD, exert much of their influence through their interaction with the endocannabinoid system (ECS).

The ECS is involved in many processes in the body, including inflammation, pain, and immune function, just to name a few.

The ECS is made up of endocannabinoids, their receptors, and enzymes.

In some animals studies, antagonists of the ECS receptor CB1 have been found to reduce the threshold of seizures, with CBD working as an antagonist on these receptors. (1)

While this is one possible way that CBD may produce anti-convulsant effects, there is much more research that needs to be conducted to fully understand how CBD affects the body.

Side Effects of CBD

One of the main side effects of CBD has to do with interactions with certain drugs. For this reason, it is important to talk to your doctor before adding in CBD as a daily supplement.

As the above studies have noted, CBD in high doses can lead to a variety of side effects, including diarrhea, fatigue, and many others. In the case of researchers determining the safety profile for those with epilepsy, most of the side effects were deemed mild to moderate, with CBD exhibiting an adequate side effect profile.

In lower doses, CBD appears to have even fewer side effects.

CBD for Epilepsy – Conclusion

With so many suffering from epilepsy that is not easily treated with current pharmaceuticals, the possibility of CBD as a treatment option for epilepsy is promising.

Both in vitro and in vivo studies have shown cannabidiol to reduce seizure frequency with mostly mild to moderate side effects.

As CBD can interfere with certain medications, it is best to speak with your doctor before using cannabidiol as a daily supplement.