Can CBD oil help with epilepsy?
The popular wellness product CBD (cannabidiol) is one of a range of compounds called cannabinoids found in the cannabis sativa plant. It’s sold in a variety of formats, but is best known as a bottled oil, which is taken orally or sublingually (as droplets placed under the tongue).
Unlike the psychoactive cannabinoid THC, CBD won’t get you high – in fact it’s usually extracted from low-THC strains of cannabis called hemp – but there is growing evidence that it can help with a variety of health conditions including certain types of epilepsy.
What is epilepsy?
People with epilepsy experience uncontrollable seizures or fits caused by bursts of electrical activity in the brain.
There are a variety of different types of seizure, including the following:
- clonic seizure – jerking and shaking
- absence seizure – staring blankly into space with a loss of awareness
- tonic / 'drop' seizure – sudden stiffening of the muscles, often leading to falls
- simple partial / focal / aura seizure – unusual physical sensations, smells or tastes, déjà vu, sudden intense emotions
- atonic / akinetic / 'drop' seizure – sudden complete relaxation of the muscles leading to collapse
- febrile convulsions – longer lasting seizures accompanied by a high temperature
There are numerous types of epilepsy with varying combinations of seizure types. They begin at different stages of life and have causes ranging from genetic disorders to illness or injury.
Can CBD oil help epilepsy and seizures?
One of only two CBD-based medicines approved in the United Kingdom is used to treat certain types of epilepsy, often in combination with other anti-epileptic drugs.
Epidyolex (spelt Epidiolex in the US and elsewhere) contains purified CBD and can be prescribed by specialist doctors for two types of rare, early-onset epilepsy called Lennox–Gastaut Syndrome and Dravet Syndrome.
The studies outlined below show that Epidyolex may help reduce seizures in both of these syndromes – as well as in the genetic condition tuberous sclerosis and several other forms of epilepsy – although in most cases at dosages much higher than those recommended for general CBD users.
Lennox-Gastaut Syndrome (LGS) occurrs in 1-5% of children with epilepsy, causing atonic and tonic seizures, both of which can result in damaging falls.
Two clinical studies conducted over a 14-week period investigated the effectiveness of Epidyolex for LGS patients aged between 2 and 55 years old. Patients on daily dosages of 10mg of Epidyolex per kg of body weight showed a 36% median average reduction in the frequency of seizures, while those on 20mg per kg showed a median reduction of 38% and 41% in each of the two studies.
Reduction in the frequency of seizures was seen within four weeks and maintained over the remainder of the treatment period. In both studies, some patients given Epidyolex reported no seizures at all.
Dravet Syndrome is thought to occur in just 2 or 3 out of every 500 children with epilepsy. It causes a range of seizures including tonic and atonic, clonic – jerking and shaking – and longer febrile seizures.
A clinical 14-week trial involving 120 Dravet Syndrome patients aged 2 to 18, taking 20mg per kg of Epidyolex, showed a median reduction in seizures of 39%. As with the Lennox-Gastaut studies, some subjects experienced no seizures at all during the study period.
Tuberous sclerosis complex
People with the genetic condition tuberous sclerosis develop (generally benign) tumours around their bodies. Tumours in the brain can cause epileptic seizures.
A study involving 224 tuberous sclerosis patients aged 1 to 65 given daily doses of 25 mg per kg of Epidyolex saw a median average reduction in seizures of 43%.
Other types of epilepsy
A 2018 study reviewed the results of Epidyolex treatment in patients with four other types of treatment-resistant childhood-onset epilepsy: CDKL5 deficiency disorder, Aicardi syndrome, Doose syndrome and Dup15q syndrome.
After 12 weeks, the median average number of seizures had reduced by more than 50%. The review concluded that there was evidence “for the long-term safety and efficacy of CBD” in treating all four forms of epilepsy, and that further clinical trials were warranted.
How does CBD decrease epilepsy seizures?
It’s currently unclear exactly how CBD is able to reduce the frequency of seizures in epilepsy patients. However, there are several candidates among the bio-chemical mechanisms in the nervous system, which may work separately or in combination to combat the bursts of abnormal brain activity that cause seizures.
- the receptor GPR55, which is known to interact with CBD and is more common among epileptics in the hippocampus, a region of the brain associated with epilepsy
- the receptor TRVP1, which is involved in increasing synaptic activity and can be desensitised by CBD use
- the anti-convulsant compound adenosine, whose levels may be increased by CBD
Researchers are not yet at the stage of being able to confirm how CBD reduces epilepsy seizures but studies have concluded that “CBD reduces neuronal excitability” through its interactions with GPR55, TRVP1 and adenosine.
Can CBD oil increase seizures?
As we’ve seen, studies suggest that purified CBD can reduce the frequency of seizures in some patients suffering from certain types of epilepsy.
However, one small retrospective study presents evidence that non-medical CBD can actually increase seizures. The research, published in the scientific journal Neurology, looked at the experiences of 31 patients with a range of epilepsy types, including 32% with Lennox-Gastaut syndrome and 6% with Dravet syndrome, and found that patients on non-medical CBD saw a 70% increase in overall seizures, while the prescription CBD group had 39% reduction.
It's possible these results may be due to impurities in the non-pharmaceutical CBD, perhaps including significant levels of THC. This serves as a reminder that even ordinary CBD users should only choose a trustworthy brand of CBD oil that provides independent laboratory tests demonstrating its content, since many have been shown to contain higher than recommended levels of THC and other substances.
However, a wider-ranging review of research published in 2018 contradicts the Neurology study, showing that a greater number of patients – 71% – reported improvements in seizures after using CBD-rich cannabis extracts than those using purified CBD (46%).
CBD and Epidyolex side-effects
Clinicians generally consider CBD 'well tolerated', meaning it is rare for subjects to leave trials due to adverse effects. In Epidyolex studies, drop-out rates ranged from 2.7% up to 11.8% when higher dosages were given.
The majority of general CBD users don’t experience side-effects and when they do they tend to be relatively minor. Dry mouth and tiredness/fatigue are most common but diarrhoea, appetite changes, irritability and nausea are also reported.
In Epidyolex users, who are generally on high doses of CBD, tiredness, lethargy and sedation appear to be the most prevalent side-effects, experienced by 32% of patients.
Epidyolex may also lead to increased levels of enzymes called transaminases – which can be related to liver damage – particularly in patients who also take the anti-epileptic valproate. In these cases, the dosage of Epidyolex may be reduced or even stopped.
In rare cases – around 1 in 530 people – Epidyolex has also been linked to a small increase in the risk of suicidal thoughts.
CBD and drug interactions
CBD inhibits certain enzymes responsible for metabolising a range of medications, including but not limited to those that carry a grapefruit warning. This can lead to unsafe levels of the drugs in the body and accentuated side-effects. Therefore, if you are on any medication you should not use CBD without consulting your doctor.
When taken with Epidyolex, the anti-epileptic valproate increases the incidence of potentially damaging transaminases in the liver.
Substances, including alcohol, that act as central nervous system depressants may increase the sedative effects of Epidyolex.
Taking Epidyolex may also increase the side-effects of a number of other anti-epileptic drugs.
Conversely, certain drugs can also reduce the effect of CBD. In some cases, this may lead to doctors reducing the dosage of these drugs or increasing the dosage of Epidyolex in patients with epilepsy.
The author of this article is not a medical expert and nothing in this article constitutes medical advice or gives rise to a medical practitioner/patient relationship. You should seek specialist medical advice where required. Never disregard professional medical advice or refrain from seeking it because of something you have read here.