Can CBD Help With Epilepsy?

Epilepsy affects approximately 50 million people worldwide and about one third of them do not achieve seizure control even with conventional antiepileptic drugs. That is precisely why CBD for epilepsy has become the most intensively researched medical application of cannabinoids over the past decade — and its results led to the creation of the first plant-derived CBD medicine approved by the European Medicines Agency. In this article we will cover what clinical research actually shows, how CBD suppresses seizures in the brain, and what the difference is between the approved drug Epidyolex and ordinary CBD oils.

What Is Epilepsy and Why Does Conventional Treatment Fall Short

Epilepsy is a chronic neurological disorder characterised by recurrent unprovoked seizures caused by abnormal electrical activity in the brain. Seizures can take many forms — from brief absences (micro-seizures) through tonic-clonic (grand mal) episodes to complex partial seizures with impaired consciousness.

Standard treatment involves antiepileptic drugs (AEDs), and about 70% of patients achieve adequate seizure control. The problem lies with the remaining 30% — these are patients with so-called pharmacoresistant or drug-resistant epilepsy, where even a combination of several medications fails to manage the seizures. It is this group that has driven decades of research into CBD for epilepsy.

The most difficult-to-treat forms of childhood epilepsy include:

• Dravet syndrome — a rare, genetically determined epilepsy that appears in the first year of life and often means lifelong seizures with a severe impact on development
• Lennox-Gastaut syndrome (LGS) — a complex childhood epilepsy with various seizure types including drop seizures
• Tuberous sclerosis complex (TSC) — a genetic disorder involving benign tumours in the brain, with 80–90% of patients having epilepsy
• Sturge-Weber syndrome, CDKL5 encephalopathy, Doose syndrome and other rare encephalopathies

For the families of these patients, CBD was first a topic of internet discussions, then the subject of serious scientific attention — and after 2017 it became part of official medicine.

CBD for Epilepsy Has the Strongest Scientific Evidence in Cannabinoid Research

Across the full spectrum of CBD health applications (anxiety, pain, sleep, skin conditions, PTSD), epilepsy is the area where cannabidiol has the best clinical evidence and regulatory approval. Here is how that came about.

Epidyolex — the First CBD Drug Approved in Europe

In June 2018 the US FDA approved the first CBD-based medicine under the name Epidiolex (in Europe from September 2019 as Epidyolex) — an oral solution containing highly purified cannabidiol (>98%) extracted from cannabis.

In the European Union, Epidyolex is approved as adjunctive (add-on) treatment together with clobazam for:

• Lennox-Gastaut syndrome in patients aged 2 years and older
• Dravet syndrome in patients aged 2 years and older
• Tuberous sclerosis complex (TSC) in patients aged 2 years and older (EU label extension in 2021)

It is a prescription-only medicine, which may only be prescribed by a neurologist or epileptologist with experience in treating these syndromes. This detail is crucial — we will return to it below.

Approved Indications and Regulatory Position

The European Medicines Agency (EMA) based its approval on five clinical studies in more than 900 patients. No other cannabinoid (including THC in various pharmaceutical forms) has reached this level of regulatory approval for epilepsy. Epidyolex is therefore the first plant-derived CBD medicine in European history with a full marketing authorisation.

What Clinical Studies Found About CBD for Epilepsy

The scientific breakthrough came with several randomised, double-blind trials that formed the basis of regulatory approval.

Dravet Syndrome — Devinsky 2017, NEJM

The landmark study by Devinsky and colleagues published in the New England Journal of Medicine in 2017 included 120 children and young adults with Dravet syndrome. Patients received 20 mg/kg/day of CBD or placebo for 14 weeks as an add-on to standard treatment.

Results were as follows:

• Frequency of convulsive seizures fell from a median of 12.4 to 5.9 seizures per month in the CBD group
• In the placebo group the decline was only from 14.9 to 14.1 seizures
• 43% of patients in the CBD group achieved at least a 50% reduction in seizures (vs. 27% in placebo)
• 5% of patients in the CBD group were seizure-free during the study

Lennox-Gastaut Syndrome — Thiele 2018, Lancet

The second key study published in The Lancet included 171 patients with LGS. After 14 weeks of CBD treatment:

• Drop seizures (falls with risk of injury) decreased by 43.9% in the CBD group
• In the placebo group the reduction was only 21.8%
• A third parallel study showed reductions in drop seizures of 41.9% at 20 mg/kg/day and 37.2% at 10 mg/kg/day

Tuberous Sclerosis Complex (TSC)

The GWPCARE6 study led to the extension of Epidyolex approval for patients with TSC. CBD reduced TSC-associated seizure frequency significantly compared to placebo, and this effect was maintained over 14–16 weeks of treatment.

Real-World Practice and Off-Label Use

Beyond the approved indications, researchers are investigating CBD in other forms of pharmacoresistant epilepsy. A study published in PMC in 2024 prospectively followed paediatric patients who began CBD for various forms of drug-resistant epilepsy. Results show a sustained effect even after 18 months of treatment with an acceptable safety profile.

In clinical practice, CBD for epilepsy (outside approved indications) is also being studied in:

• Sturge-Weber syndrome — the Kennedy Krieger Institute recorded more than 50% seizure reduction in all children monitored
• CDKL5 encephalopathy — a rare childhood epilepsy with severe developmental impairment
• Doose syndrome (myoclonic-atonic epilepsy)
• Febrile seizures associated with SCN1A mutations
• Post-traumatic epilepsy in adults following brain injuries

Paediatric neurology centres across Europe are participating in international registries, and some patients with pharmacoresistant epilepsy already have experience with Epidyolex.

Epilepsy in Adults and CBD

Although most clinical studies on CBD for epilepsy were conducted in children with rare syndromes, the situation for adult patients is more complex. Idiopathic generalised epilepsy and focal epilepsies in adults are usually well controlled by modern AEDs (lamotrigine, levetiracetam, valproic acid, oxcarbazepine). For patients who do not respond adequately, a neurologist may consider Epidyolex off-label, but the decision depends on the specific diagnosis and seizure history.

For adults with partially controlled epilepsy there is an important warning — never modify your own AED treatment without consulting a neurologist, and do not experiment with high doses of OTC CBD oil. Abrupt cessation or dose reduction of prescribed AEDs can trigger status epilepticus, a life-threatening condition.

How CBD for Epilepsy Acts in the Brain

The anti-seizure mechanism of CBD is different from other antiepileptic drugs and is still not fully understood. We do know, however, that CBD acts through multiple molecular pathways simultaneously:

• TRPV1 channels — CBD influences calcium movement through these channels, which is important for electrical signal transmission in nerve cells
• Adenosine system — adenosine in the brain acts as a natural seizure “brake” and CBD increases its availability
• GPR55 receptor — CBD is an antagonist of GPR55, which is involved in excessive electrical activity during seizures
• 5-HT1A receptor — the serotonin pathway, which modulates anxiety and certain seizure types
• Glycine receptors — involved in dampening neuronal excitability

Crucially, CBD for epilepsy does not act through the classical cannabinoid receptors CB1 and CB2 — which is why it has no psychoactive effects like THC. It is an entirely different pharmacological profile, even though both compounds come from the same plant. For more on how CBD acts in the body generally and which receptors it reaches, see the article CBD drops and their effects.

CBD also has neuroprotective and anti-inflammatory properties that may help protect nerve cells from damage caused by repeated seizures. This aspect is particularly important in childhood epilepsy, where uncontrolled seizures can affect brain development.

Clinical CBD Dosing for Epilepsy

Clinical doses of CBD for epilepsy are significantly higher than for everyday wellness use. According to the official Epidyolex prescribing information:

• Starting dose: 2.5 mg/kg twice daily (i.e. 5 mg/kg/day)
• Maintenance dose after 1 week: 5 mg/kg twice daily (10 mg/kg/day)
• Maximum dose: 10 mg/kg twice daily (20 mg/kg/day)

In practice, for a child weighing 30 kg this means a starting dose of 150 mg CBD per day and a maintenance dose of 300 mg CBD per day. For comparison, a typical adult wellness dose is 15–30 mg per day. To understand the principles of safe dose escalation, read the article How to dose CBD: how much to take and how to start.

At every dose increase it is necessary to monitor liver enzymes and the plasma levels of any other AEDs the patient is taking.

Epidyolex vs. Regular CBD Oil for Epilepsy — a Critical Difference

This is the most important section of the article, because many parents and patients incorrectly assume that a regular CBD oil from an online shop is equivalent to Epidyolex. It is not. The differences are fundamental:

Parameter	Epidyolex (medicine)	OTC CBD oil (food supplement)
Regulation	EMA-registered medicine	Food supplement
Sales	Prescription only	Freely available
Indication	Specific diagnoses (LGS, Dravet, TSC)	No medical indications
Concentration	100 mg/ml, precisely dosed	Typically 5–15% (50–150 mg/ml)
Purity	High-purity CBD isolate (>98%)	Most often full-spectrum
Supervision	Prescribed by neurologist, liver monitoring	No medical supervision
Cost	Covered by insurance when indicated	Out-of-pocket

Regular CBD oil (including our products from Konopná farma Liptov) is not a medicine and must not be used to treat epilepsy. If you or someone in your family suffers from epilepsy — especially childhood or pharmacoresistant epilepsy — the first step must be consultation with a neurologist, who will assess whether Epidyolex or another conventional treatment is indicated.

For adults with occasional mild symptoms, full-spectrum CBD oil 15% full spectrum may be a supportive part of overall lifestyle management, but always after consulting a doctor and never as a substitute for prescribed treatment. When choosing, look for purity certificates, declared CBD content, and the origin of the hemp — more on quality criteria can be found in the broader CBD oils category on our website.

How to Obtain Epidyolex

For patients who might benefit from Epidyolex treatment, the process is as follows:

• Diagnosis by a neurologist or paediatric epileptologist — confirmation of the specific syndrome (LGS, Dravet, TSC) using EEG, MRI, and where indicated genetic testing
• Exhaustion of conventional treatment — Epidyolex is generally prescribed only after failure of at least two AEDs
• Indication assessment — the neurologist evaluates benefit vs. risk and interactions with current medication
• Prescription and reimbursement request — Epidyolex is EU-approved and in some cases covered by health insurance
• Regular monitoring — liver enzymes before treatment, then at 1, 3 and 6 months

Paediatric neurology centres and adult neurology clinics at major hospitals across the EU have experience with the treatment. Ask your GP for a referral to a specialist epilepsy service.

Side Effects of CBD for Epilepsy and Interactions With AEDs

CBD for epilepsy has a fairly well-characterised side-effect profile based on clinical studies with Epidyolex. The most common effects at clinical doses are:

• Somnolence, sedation, lethargy — the most frequent side effect, often resolves over time
• Decreased appetite and weight loss
• Diarrhoea — typically in the first weeks
• Elevated liver enzymes (ALT/AST) — risk especially in combination with valproate
• Fatigue and weakness
• Rash — rarely

The most important drug interactions that a prescribing doctor must monitor:

• Clobazam — CBD raises clobazam blood levels, which can increase sedation; a clobazam dose reduction is often needed
• Valproate — the combination substantially increases risk of hepatocellular injury; regular liver enzyme monitoring is required
• CYP2C19 substrates (e.g. clobazam, phenytoin) — CBD alters their metabolism
• Warfarin and other anticoagulants
• Oral contraceptives — effectiveness may be reduced

Before starting Epidyolex, liver function tests (ALT, AST, bilirubin) must be performed and are repeated at 1, 3 and 6 months. Use during pregnancy is not recommended based on findings from animal studies.

Summary: Where We Stand With CBD and Epilepsy Research in 2026

Across all health applications, CBD for epilepsy has the strongest scientific evidence and, thanks to the NEJM and Lancet studies, has become part of mainstream medicine. In Europe the registered medicine Epidyolex is available for three specific epileptic syndromes and its efficacy is supported by studies in more than 900 patients. If you or someone close to you is dealing with epilepsy, the first step is consultation with a neurologist or epileptologist — ordinary full-spectrum CBD oils from our farm are food supplements and cannot replace prescribed treatment for a diagnosis as serious as epilepsy.

Sources

• Devinsky O et al. Trial of Cannabidiol for Drug-Resistant Seizures in the Dravet Syndrome. New England Journal of Medicine, 2017;376(21):2011–2020
• Thiele EA et al. Cannabidiol in patients with seizures associated with Lennox-Gastaut syndrome: a randomised, double-blind, placebo-controlled phase 3 trial. The Lancet, 2018
• European Medicines Agency, Epidyolex — Summary of Product Characteristics
• FDA, EPIDIOLEX (cannabidiol) oral solution — Prescribing Information, 2025
• Consensus Panel, Recommendations for the Optimization of EPIDIOLEX Treatment for Seizures, Epilepsia Open, 2024
• WHO Expert Committee, Cannabidiol (CBD) Critical Review Report, 2018