Introduction

Epilepsy is a chronic brain disorder where neurons in the brain send wrong signals and cause seizures.¹ A seizure is a sudden burst of electrical activity in the brain,² which causes the patient to lose consciousness and often experience repeated shaking movements.² Some people recover immediately after a seizure, while some people may need more time and experience fatigue and confusion.¹

Epilepsy itself can be caused by many diseases and can cause different types of seizures. The seizures themselves can be triggered by stress, drinking alcohol, dehydration, exposure to toxins, hormonal changes, sleep deprivation and visual disturbances.¹ Treatment of epilepsy aims to reduce the severity and amount of seizures,³ with measures such as antiepileptics and surgery.³ 

A treatment option of epilepsy is cannabidiol. Cannabidiol is the second most prevalent active ingredient in cannabis.⁴ On its own, it does not cause a high,⁴ due to it being non-psychoactive. It is a prescribed agent for epilepsy if you suffer from a rare type of epilepsy that is not improving with regular treatment.

This article will explore how CBD can be used to treat epilepsy, especially to affect seizure thresholds. 

Seizures thresholds and CBD

A seizure threshold can be measured by the time needed for a seizure to occur, the amount of convulsant drug needed to induce a seizure.⁵ Lowering the seizure threshold would lead to seizures, while increasing the seizure threshold would lead to an anticonvulsant effect.⁵

There are different factors that can raise or lower the seizure threshold and have an effect on patients. For example, missing a dose of antiseizure medication may lower the seizure threshold, as can alcohol, and brain injuries.⁶. 

CBD is licensed in epilepsy under the form - mainly - of Epidyolex for both children and adults.⁷ Epidyolex is a highly purified liquid containing CBD.⁷ It is usually prescribed to patients with rare forms of epilepsy, such as Lennox-Gastaut and Dravet syndrome.⁷

There is not much research into how CBD affects epilepsy due to the legal restrictions on it, however there are some studies that hypothesise how it interacts with the brain to raise the seizure threshold. One such study interacts with T-type calcium channels by having CBD cause a blockage in these channels.⁸ This mechanism could give an explanation for the anti-epileptic effects, but there are no studies to confirm this.⁸ Receptors may also have a role in the anti-epileptic effects; for example, serotonin coupled to G-protein-coupled receptors, along with 5-HT receptors and opioid receptors all may play a role in the anti-epileptic effects of CBD.⁸

It is important to note that there may be some factors that affect seizures thresholds that we are not aware of. The brain is so complex and difficult to study, so we still do not know much about all its mechanisms and how it works.⁸ We have an understanding of how neurons interact and how neurobiology works, but how the brain as a whole operates is still a mystery to us.⁸ We may not fully comprehend seizures and seizure-thresholds, but there is a definite relationship between CBD and being able to raise them and decrease epileptic attacks in some rare forms of epilepsy. 

Challenges to using CBD Therapy for seizures thresholds

There are some considerable challenges to using CBD to affect seizures thresholds. One such challenge is that, due to the lack of research into the precise ways in which CBD works, we can have a large variability of responses depending to patient factors. Just because CBD can raise the seizure threshold in some patients, it doesn’t mean that it will do the same in the other patients. This can be quite disappointing for patients, as it gives them false hopes and does not reach the desired targets.

CBD can also have some serious side effects. Although it is not psychoactive - it does not give you a high - it can make patients drowsy, sleepy and lose their appetite.⁹ It can even bring patients to have diarrhoea and experience suicidal thoughts, which can have a severe impact on the patient’s quality of life.⁹ Although there are side effects to every medication, some patients may be put off from trying CBD for their seizures because they fear being sleepy, drowsy or experiencing the suicidal thoughts.⁹

CBD can also interact with other medications, some which are not used commonly, some which are used very commonly.¹⁰ Some of the most severe interactions that CBD can have with other medications include: warfarin (blood-thinner), amiodarone (medication for the heart), levothyroxine (medication for thyroid deficiency) and several anti-seizure medications (i.e clobazam, lamotrigine, valproate).¹⁰ Taking these medications and taking CBD as well may lead to these medications not working anymore, or malfunctioning and having adverse reactions. It is important to consider these when prescribing medications to patients, to avoid their other medications to stop working and bring back their symptoms. There may be other options to swap their medications, or they may have to try something else rather than CBD.

FAQs

Who is most likely to get epilepsy?

Anyone can develop epilepsy, but it is most common in young children and adults. Some risk factors for epilepsy include:¹¹

• Genetic factors
• Infection
• Traumatic brain injuries
• Stroke
• Alcohol use
• Hormonal changes¹¹

Can I get CBD over-the-counter?

CBD is on-prescription only. You will need your doctor’s prescription to access it.

When do I need to call an ambulance for a seizure?

If someone near you is having a seizure, you should call an ambulance if:

• It’s their first seizure
• Their seizure lasts for more than 5 minutes
• They are not regaining consciousness
• They keep seizing¹

Summary

Seizures happen when the brain sends too many electric signals, causing the affected person to lose consciousness and experience shaking “fits” - in most cases. Seizures can happen to people who suffer with epilepsy, which can be triggered by many factors such as missed medications, lack of sleep or traumatic brain injuries. A seizure threshold is described as the time needed for a seizure to occur, and it can be affected by factors such as medications. CBD is a component of cannabis which is non-psychoactive, and it can be prescribed to people with rare forms of epilepsy. It is not quite known by which mechanisms it does help, but there are some benefits for people who cannot be on regular anti-epileptics. Some challenges to giving CBD to raise seizure threshold is that it may interact with other medications the patient takes, as well as its side effects and variability in how the patient responds. 

If you suffer from seizures and conventional treatment is not working, talk to your doctor about whether CBD may be an option for you.