Can Weed Cause Seizures? Exploring the Link Between Cannabis and Seizures

Medically Reviewed By Eloise Theisen, RN, MSN, AGPCNP-BC

Research into the effects of cannabis (weed) on the brain is ongoing. However, it may be possible for high-potency cannabis to induce seizures in some people. Most people either inhale or eat the drug to induce a “high.”

The terms “weed” and “marijuana” have historically racist roots and connotations. For this reason, we will use the medical term “cannabis” where possible.

Cannabis (weed) is the most popular Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source drug in the United States that’s still designated illegal at the federal level. While states may have different laws regulating cannabis, the U.S. government still considers it illegal. Some people say cannabis provides them with a sense of calmness and euphoria. Other people report that the drug even has beneficial effects on seizures.

This article will explain the link between cannabis and seizures.

Can weed cause seizures? 

A closeup of a cannabis plant
Ani Dimi/Stocksy United

Cannabis (weed) contains a group of compounds known as cannabinoids. Cannabinoids are responsible for the drug-like effects of cannabis on the brain. 

Tetrahydrocannabinol (THC) and cannabidiol (CBD) are both types of cannabinoids. Studies into the effects of cannabinoids on seizures have had mixed results.

Some papers claim that cannabinoids may have a positive impact on epilepsy. Other studies suggest that the substances can worsen the condition.

It is worth noting that both schools of thought base their claims on preliminary data. As such, further research is necessary to fully understand cannabis’s influence on seizures.

Still, researchers seem to agree that high-potency cannabis may have harmful effects on the body.

A 2017 study Trusted Source International Journal of Obesity Peer reviewed journal Go to source that administered THC and the synthetic cannabinoid JWH-018 to adult male mice yielded two key findings:

  1. The mice experienced seizures shortly after receiving 10 milligrams of THC per kilogram of body weight (mg/kg) or 2.5 mg/kg of JWH-018. Respectively, these doses are equivalent to 49 mg of THC and 12 mg of JWH-018 in humans.
  2. JWH-018 triggered more frequent seizures than THC.

More research is necessary to determine whether similar effects may occur in humans.

A study from 2011 Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source observed the effects of synthetic cannabinoids on 2 humans with no prior history of neurological disease. The study also shared two main findings:

  1. Both humans had a seizure after smoking the drug.
  2. Spice may be more toxic than regular cannabis.

In addition, synthetic THC interacts with the brain differently than plant-based THC. This difference may explain the increased seizure activity.

Cannabis as a treatment for epilepsy 

Clinicians have prescribed medical cannabis to treat epilepsy for many years. However, the results have varied.

In a 2018 literature review Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source , researchers analyzed six studies wherein people with epilepsy received regular antiepileptic drugs alongside either a placebo or CBD.

Two people in one trial had no seizures during the entire 3 months of treatment. However, the third person only experienced partial improvement. The fourth person had no improvement at all.

In another trial from the review, 4 in 8 people became seizure-free after the treatment period. However, three people saw partial improvement, and the remaining person did not experience any effect.

Researchers are still trying to understand the true impact of cannabis on epilepsy.

How does weed affect the brain? 

According to the National Institute on Drug Abuse (NIDA) Trusted Source National Institute on Drug Abuse Governmental authority Go to source , the chemicals from cannabis (weed) travel through the bloodstream and into the brain. Inhalation of these chemicals leads to the fastest absorption, while oral consumption is slower. According to research from 2017, topical application of products containing THC does not produce the effects that result from inhalation or oral consumption.

In the brain, cannabis chemicals bind to special molecules that influence:

  • thoughts
  • pleasure
  • sensory and time perception
  • memory
  • concentration
  • movement
  • coordination

This binding disrupts many mental and physical processes. It also causes the characteristic effects of cannabis use. Additionally, it interferes with the brain’s neural network, causing it to act unusually.

In particular, THC can change the behavior of the hippocampus and the orbitofrontal cortex. These two areas of the brain enable memory formation and focus.

What effects does weed produce in people? 

According to the Centers for Disease Control and Prevention (CDC) Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source , the effects of cannabis (weed) can vary depending on certain factors, such as:

  • the amount, concentration, and strength of THC in the cannabis
  • frequency of use 
  • age of first use
  • presence of other substances in the body, such as tobacco or alcohol

Many people who smoke cannabis report pleasant experiences, such as Trusted Source National Institute on Drug Abuse Governmental authority Go to source :

  • euphoria
  • laughter
  • heightened sensory perception
  • relaxation
  • altered perception of time 
  • increased appetite

Others experience a significantly different range of effects, such as:

  • anxiety
  • fear
  • distrust
  • panic
  • hallucinations
  • delusions
  • loss of personal identity

Some people may also experience:

If you need help to stop using cannabis, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) at 1-800-662-HELP (1-800-662-4357).


Cannabis (weed) is the most common illegal drug in the U.S. Many people experience euphoria, relaxation, and other pleasant effects when they take the drug. Others experience adverse effects, such as anxiety and distrust.

As of today, researchers are unsure about the full impact of cannabis on seizures. Some studies say cannabis may be beneficial for managing seizures. Other papers argue that the opposite is true.

Still, researchers agree that high-potency cannabis may cause seizures and other negative bodily effects.

Other harmful effects of cannabis may include addiction and increased risk of vascular diseases. Contact your doctor to discuss the possible effects of cannabis or to get help quitting.

  1. Alexander, J. C., et al. (2019). A review of the anesthetic implications of marijuana use.
  2. Brain health. (2020).
  3. Cannabinoid. (n.d.).
  4. de Havenon, A., et al. (2011). The secret “spice”: An undetectable toxic cause of seizure.
  5. Gaston, T. E., et al. (2018). Cannabis for the treatment of epilepsy: An update [Abstract].
  6. Hess, C., et al. (2017). Topical application of THC containing products is not able to cause positive cannabinoid finding in blood or urine.
  7. Katona, I. (2015). Cannabis and endocannabinoid signaling in epilepsy. Endocannabinoids.
  8. Malyshevskaya, O., et al. (2017). Natural (∆9-THC) and synthetic (JWH-018) cannabinoids induce seizures by acting through the cannabinoid CB1
  9. Solomon, R. (2020). Racism and its effect on cannabis research.
  10. What are marijuana's effects? (2020).
  11. Zaheer, S., et al. (2018). Epilepsy and cannabis: A literature review.

Medical Reviewer: Eloise Theisen, RN, MSN, AGPCNP-BC
Last Review Date: 2022 Oct 20
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