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Seizures are caused by changes in the electrical activity in your brain. There are many different types of seizures, and potential causes can include:

Cannabidiol (CBD) is a chemical found in the cannabis plant that people often take to manage chronic pain or to reduce their anxiety symptoms. Unlike tetrahydrocannabinol (THC), CBD is not euphoric or impairing.

CBD oil may be able to help treat some types of seizures.

In this article, we break down what the latest studies have found and look at the potential side effects.

It isn’t known exactly how CBD helps prevent seizures.

Your body contains a system of neurotransmitters and receptors called the endocannabinoid system. This system is thought to help regulate functions in your body such as appetite, sleep, and pain, as well as your immune system response.

It’s thought that CBD can modify these functions by interacting with receptors in your endocannabinoid system.

Animal research suggests CBD’s antiseizure effects might come from reducing neuron excitability by acting on two groups of receptors called GPR55 and TRPV1 receptors.

Currently, a prescription drug CBD called Epidolex is approved by the Food and Drug Administration (FDA) to treat Lennox-Gastaut and Dravet syndromes, two rare forms of epilepsy. It’s also FDA-approved to treat seizures caused by the genetic disorder tuberous sclerosis complex.

Research on CBD oil’s ability to treat seizures is ongoing. The most rigorous studies have been performed on people with one of the three conditions that CBD oil is FDA approved to treat.

CBD for Lennox-Gastaut syndrome

Lennox-Gastaut syndrome makes up about 2 to 5 percent of childhood epilepsy cases.

Two 14-week clinical trials examined the effectiveness of Epidolex for treating seizures in people with Lennox-Gastaut syndrome.

Study 1

In the first study, researchers compared the antiseizure effect of 20 milligrams per kilogram (mg/kg) of Epidolex per day with a placebo.

They found:

  • Half of the participants who took Epilolex experienced 44 percent fewer seizures.
  • Half of the participants in the placebo group experienced 22 percent fewer seizures

Study 2

The second study compared the effects of 10 mg/kg and 20 mg/kg daily doses of Epidolex with a placebo.

Both Epidolex groups had significantly fewer seizures than the placebo group.

  • Half the participants who took 20 mg/kg of Epidolex per day experienced 42 percent fewer seizures.
  • Half the participants who took 10 mg/kg per day experienced 37 percent fewer seizures.
  • Half the participants in the placebo group experienced 17 percent fewer seizures.

CBD for Dravet syndrome

Dravet syndrome is a rare form of epilepsy that causes seizures that don’t respond well to medication.

In a clinical trial, researchers compared the effect of 20 mg/kg of Epidolex taken daily with a placebo in participants age 2 to 18.

The researchers found that participants who took Epidolex experienced a significant drop in seizure frequency (39 percent decrease), compared with the placebo group (17 percent decrease).

CBD for tuberous sclerosis complex

Tuberous sclerosis complex is a rare condition that occurs in about 1 in 6,000 people. It’s a genetic disorder that causes noncancerous tumors to grow in various parts of your body. Tumors in the brain lead to seizures in some people.

In a clinical trial, researchers examined the effects of 25 mg/kg and 50 mg/kg of Epidolex per day, compared with a placebo, on a group of 148 patients with tuberous sclerosis complex.

The median improvement was 48 percent for the Epidolex group and 24 percent for the placebo.

CBD for other causes of seizures

Further research is needed to know if CBD is effective at treating other kinds of seizures. However, some early studies have found promising results.

Research has found evidence that CBD may enhance the effect of the medication clobazam (Onfi) often used to treat epilepsy. There’s some evidence CBD may also enhance the effect of some other antiepileptic drugs.

A 2018 study examined the effect of CBD on 55 people with one of four types of epileptic syndromes:

At baseline, the participants had an average of 59.4 seizures per month. After 12 weeks, the average went down to 22.5 per month. The improved rate persisted over the entire 48 weeks of the study.

It’s very important to work with a doctor when using CBD oil to treat seizures. Your doctor can help determine if CBD will interact with any of your current medications.

Research has found that some people report more seizures after taking CBD. Your doctor can help you monitor your seizure frequency and determine if CBD is right for you.

The recommended starting dose of Epidolex is 2.5 mg/kg twice per day. After a week, the dose can be increased to 5 mg/kg twice per day. Based on an individual’s response and tolerability, it can be increased to a maximum of 10 mg/kg twice per day.

If you’re using CBD oil for seizures, don’t stop taking it abruptly, as it may lead to an increase in seizure activity.

Both CBD and other antiepileptic drugs may increase your risk of suicidal thoughts and behaviors. This happens in about 1 in 500 people.

CBD can potentially interact with other medications used to control seizures. In some cases, it may make the medication more or less effective. Some medications that CBD is known to interact with are:

  • brivaracetam
  • clobazam
  • eslicarbazepine
  • stiripentol
  • rufinamide
  • topiramate
  • valproic acid
  • zonisamide

Unless you’re told otherwise by your doctor, you shouldn’t take CBD as a replacement for traditional medications. Your doctor can help you adjust the doses of your medication and CBD appropriately.

The most common side effects of CBD include:

CBD in combination with some medications may increase your risk of liver damage.

Commercially available CBD oils aren’t FDA regulated, and there’s a high risk of mislabeling. These products may contain heavy metals or other contaminants that may have negative health consequences.

No matter why you’re taking CBD, it’s important to use a CBD oil that’s been third-party tested for impurities.

In some studies, people have experienced an increased number of seizures after using cannabis products.

In a 2018 review of studies, researchers found that cannabis products rich in CBD seem to be more effective at reducing seizure frequency than pure CBD, but more research is needed.

In a 2020 study, researchers found that patients taking a commercial CBD product had a 70 percent increase in seizures, whereas the group taking prescription CBD had a 39 percent reduction.

A reason for this may be that the commercial CBD products had higher levels of THC, which can be a trigger for seizures.

While this study was small, with only 31 participants, it does reinforce the importance of using a high-quality product that’s properly labeled.

Since Epidiolex is FDA approved, it’s held to high manufacturing standards and has a consistent dose.

The FDA doesn’t regulate commercially available CBD products, so there’s a high risk that the amount of CBD and THC on the label isn’t actually what they contain.

If you’re interested in taking CBD oil to help manage your seizures, it’s important to talk with a doctor first.

Your doctor can recommend the best way to take CBD and also advise you if it has the potential to interact with any other medications you’re taking.

They can also help you track your progress over time to see if your seizure frequency is decreasing.

Research investigating CBD’s ability to treat seizures is ongoing. CBD is currently approved to treat seizures caused by two rare forms of epilepsy and tuberous sclerosis complex. Some early studies have found that CBD may also be an effective treatment for some other types of epilepsy.

In some cases, cannabis products may increase seizure frequency. If you’re dealing with seizures, it’s important to talk with your doctor before taking any cannabis products.