Medically Reviewed by
Jason Crawford

Article Last Updated on December 20, 2022

According to the National Institute on Drug Abuse (NIDA), cannabis is the most commonly used substance right after tobacco and alcohol. But, weed isn’t just used for recreational purposes alone. Medical marijuana has also been thriving as we keep on learning about its therapeutic potential.

We know that cannabis has a special way of interacting with the human brain, so what does that mean for people who suffer from epileptic seizures? There is an existing link between the use of marijuana and seizures that needs to be explored, so that’s what we’re going to talk about in this article: Can weed cause seizures?

What Are Epileptic Seizures?

Epilepsy is a neurological condition which is a common cause of seizures. An epileptic seizure is an uncontrolled disturbance in the electrical activity in the brain resulting in temporary abnormal changes in behavior, movement, or state of awareness. Not all seizures are alike and the symptoms and severity may vary. 

People who are diagnosed with epilepsy are given antiepileptic medications that are supposed to control the seizure activity and lower their frequency. Many of the people taking these medications experience side effects, so they have turned to marijuana as an alternative solution. However, is weed really safe for people with a seizure disorder?

How Weed Affects the Central Nervous System

Weed interacts with the human body through its cannabinoid receptors, most of which are located in the central nervous system, including the brain. Clusters of cannabinoid receptors can be found in key parts of the brain that govern some essential functions, such as mood, memory, movement, learning, etc. 

THC (tetrahydrocannabinol), the cannabinoid with psychoactive properties, attaches to these receptors and temporarily alters their function, resulting in a feeling also known as “the high.”

CBD (cannabidiol), on the other hand, has a different way of interacting with the body that involves only attaching to the receptors partially and using different pathways that the scientists are still discovering.

Today, weed is being used as both a recreational substance and medicine, but since it can have a notable influence on the brain, it’s important to examine whether it can actually trigger seizures in people with epilepsy (or treat them).

Can Weed Trigger Seizures?

There is one important study that looks into the effects of THC on the brain and its potential to trigger seizures. The 2017 animal model study was conducted at the University of Tsukuba in Japan and published in the journal Scientific Reports. The researchers propose that high doses of THC and synthetic forms of THC, also known as “spice”, may increase seizure activity.

They observed the behavior of rodents during the course of the study and discovered that there was seizure activity for four hours after the administration of THC, and the brain activity went back to normal by the following day. They also noted that the seizure frequency was higher in response to the synthetic form of THC.

While this discovery shouldn’t be ignored, the researchers also pointed out that for the study, they used high doses of THC that don’t necessarily reflect the doses used with recreational and medical marijuana.

Still, the effects of THC on the brain should be studied better in order to understand them fully in relation to seizures.

On the Other Hand, Scientists Discovered That CBD Has Anticonvulsant Properties

The therapeutic properties of CBD have been the basis for the medical use of marijuana even in states where recreational marijuana isn’t legal yet. CBD has anti-inflammatory, anxyolitic, antispasmodic, and anticonvulsant properties.

After years of studying its anticonvulsant properties, in 2018, the FDA (U.S. Food and Drug Administration) approved the first CBD-derived medicine called Epidiolex intended to treat two rare and severe forms of childhood epilepsy called Lennox-Gastaut syndrome and Dravet syndrome. 

Epidiolex is an oil-based Cannabis Sativa L. (hemp) extract with over 98% CBD as the main active ingredient. Clinical trials showed that the children who were given Epidiolex as opposed to a placebo drug had a reduced seizure frequency

All children were also taking other anti-seizure medications and some experienced side effects as a result of taking a higher dose of Epidiolex. The most common side effects were a change in liver function, sleepiness, lethargy, sedation, decreased appetite, rash, and sleep disturbances.

So, Is Cannabis Use a Risk Factor for People Who Suffer From a Seizure Disorder?

We all know the most common side effects of marijuana – dry mouth, red eyes, the munchies, motor impairment, and heightened anxiety, but some people with a seizure disorder may be wary and wonder if smoking marijuana may lead to new-onset seizures. 

It seems like THC could be a problematic ingredient in high doses, but based on a few studies, we can’t take this at face value. Overall, it seems like CBD is a more beneficial active ingredient in this case, so until we know more, it might be safer to stick to high-CBD strains or smoke hemp flower for an optimal CBD content.

Another measure of caution would be to always buy from trusted sellers as there is a lot of laced weed being sold on the black market. Laced weed is bad for any user, but especially for users who may be sensitive to marijuana’s chemical profile.

Final Thoughts on Weed and Seizures

Considering how cannabis impacts major parts of the brain, it’s very important to examine how this connection could affect people who suffer from epileptic seizures. 

From what we gathered so far, it seems like THC has a bigger potential to cause adverse effects and even trigger seizures when it’s in high doses or in a synthetic form. However, these findings need to be backed up by more research and case reports that are currently lacking. 

There is slightly firmer evidence about the anticonvulsant properties of CBD backed up by the FDA approving a CBD-derived medicine for the treatment of two forms of epilepsy, although the mechanism of action of CBD remains unexplored.

In any case, persons who are interested in using cannabis are advised to consult with their healthcare professional or neurologist.

Additional Sources

Devinsky, O., et al. (2014). Cannabidiol: pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders. Epilepsia, 55(6), 791–802. https://doi.org/10.1111/epi.12631  

Gaston, T. E., & Szaflarski, J. P. (2018). Cannabis for the Treatment of Epilepsy: an Update. Current neurology and neuroscience reports, 18(11), 73. https://doi.org/10.1007/s11910-018-0882-y

Gordon, Elisabeth & Devinsky, Orrin. (2001). Alcohol and Marijuana: Effects on Epilepsy and Use by Patients with Epilepsy. Epilepsia. 42. 1266-72. 10.1046/j.1528-1157.2001.19301.x.

Gordon E., Devinsky O. (1999) Marihuana: Effects on Neuronal Excitability and Seizure Threshold. In: Nahas G.G., Sutin K.M., Harvey D., Agurell S., Pace N., Cancro R. (eds) Marihuana and Medicine. Humana Press, Totowa, NJ. https://doi.org/10.1007/978-1-59259-710-9_61

Perucca E. (2017). Cannabinoids in the Treatment of Epilepsy: Hard Evidence at Last?. Journal of epilepsy research, 7(2), 61–76. https://doi.org/10.14581/jer.17012

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


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