How Cannabidiol (CBD) Works for Seizures

Kelsey Engvik MBA

Written by
June 02, 2026

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How Cannabidiol (CBD) Works for Seizures

Cannabidiol (CBD) is a non-intoxicating component of the cannabis plant. Scientific investigations over the past decade have clarified CBD’s potential as an anti-seizure medication, distinguishing its mechanism from both tetrahydrocannabinol (THC) and traditional antiepileptic drugs¹. 

CBD and the Endocannabinoid System

CBD interacts with the endocannabinoid system, a network of receptors and neurotransmitters that help regulate neural activity, immune function, and inflammation¹. 

Recent studies suggest that CBD’s action against seizures may largely involve its modulation of two types of receptors: GPR55 and TRPV1.

The hippocampus is a brain region where seizures can originate and propagate. CBD is believed to block lysophosphatidylinositol (LPI) from activating GPR55, disrupting a “positive feedback loop” that otherwise exacerbates seizure activity²˒³. Elevated LPI–GPR55 signaling can amplify nerve impulses, making seizures more likely².

By attenuating this feedback, CBD dampens network hyperexcitability, potentially offering protection against seizures even in otherwise treatment-resistant cases³. 

Moreover, CBD shows antioxidant, anti-inflammatory, and neuroprotective effects⁴˒⁵. These properties are thought to contribute to its ability to reduce neuronal excitability and promote homeostasis, thereby lowering seizure risk.

While the exact molecular pathways remain under investigation, animal and clinical data converge on the conclusion that CBD can reduce seizure frequency and severity by modulating these neural circuits¹. 

 Does CBD Work for All Types of Seizures? 

The strongest evidence for CBD’s efficacy comes from large placebo-controlled trials concerning Lennox-Gastaut syndrome (LGS), Dravet syndrome, and tuberous sclerosis complex (TSC) — rare, severe pediatric epilepsies that are often resistant to standard therapies⁶⁻⁸.

In these populations, CBD therapy (via the now FDA-approved medication Epidiolex) produced a significant reduction in total seizures, with responders typically seeing a 36–43% median decrease⁶˒⁷. Moreover, a subset of patients achieved near-complete remission, and many reported significant improvements in quality of life apart from seizure count⁷. 

Recent studies have expanded inquiry into focal-onset and generalized seizures.

CBD, generally administered as adjunctive therapy (i.e., alongside other antiepileptic drugs), was shown to reduce focal seizures with an acceptable safety profile over prolonged use⁹.

Patients with drug-resistant epilepsy — not limited to the classic pediatric syndromes — sometimes benefit from CBD, with many seeing a reduction in frequency, duration, and intensity of seizures⁹˒¹⁰.

The efficacy profile appears broad, with CBD demonstrating the ability to reduce motor, generalized, atypical absence, atonic, tonic, and myoclonic seizures¹⁰. 

However, it is essential to recognize that not all seizure types, nor all patients, respond equally to CBD. Complex motor seizures tend to respond less robustly than other types, and response rates and optimal dosing may vary with the specific epilepsy syndrome, concurrent medications, and individual genetic or metabolic factors¹¹. 

CBD and Age Groups: Efficacy in Children, Adults, and Elderly 

CBD use for seizures has been studied most robustly in pediatric populations. For example, in children aged 2–10 years with Dravet syndrome, CBD at 20 mg/kg/day cut median seizure frequency by more than half, with nearly half of patients seeing a ≥50% reduction⁶. Several meta-analyses confirm CBD is generally safe in children, though higher doses carry a greater risk of adverse events¹⁰. 

Adults with refractory epilepsy also appear to benefit from CBD, with clinical trials reporting sustained seizure reduction and stable safety profiles over four or more years of use⁹.

A study of focal-onset seizures in adults found seizure reduction across all ages, with plasma CBD levels — not age itself — determining efficacy⁹.

Limited data exist on CBD’s effects in elderly patients, but early findings suggest similar benefit and tolerability profiles, with the caveat that seniors may require closer monitoring for interactions¹¹. 

Safety, Drug Interactions, and Adverse Effects 

CBD is generally well-tolerated but can cause side effects, especially at higher doses. Common adverse events include somnolence, sedation, diarrhea, decreased appetite, fatigue, insomnia, and mood changes¹². Rarely, paradoxical seizure increases can occur¹².

Drug interactions are notable — CBD can raise plasma levels of antiepileptics such as clobazam and valproic acid due to inhibition of cytochrome P450 enzymes¹³˒¹⁴. 

CBD can commonly interact with a wide range of conventional medications that children are not commonly using, but adults, particularly older adults, may be. In rare instance, particularly at higher CBD doses, transaminitis and other evidence of liver toxicity has been noted.

Monitoring by a specialist, potential dose adjustments, and careful integration with other therapies are essential.

Summary: Association of Cannabinoid Specialists Perspective 

CBD is a scientifically validated adjunct therapy for treatment-resistant epilepsy. Its efficacy is established for LGS, Dravet, and TSC, and growing evidence supports broader use in other seizure types and age groups⁶⁻¹⁰.

While not universally effective, its favorable risk–benefit profile makes it a valuable tool when used under professional supervision.

Clinicians should tailor treatment based on seizure type, patient age, comorbidities, and concurrent medications, integrating CBD into a comprehensive epilepsy care plan.

 

Interested in learning about more cannabinoids? Take the ACS course on Minor Cannabinoids: What Do We Really Know?

 

References: 

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