About 30% of epilepsy patients don't respond to standard medications—and the clinical evidence for CBD and THC as anticonvulsants has been growing, though regulatory barriers persist.
Epilepsy patients exploring cannabis options, neurologists weighing the evidence, and families navigating treatment-resistant seizures.
What the researchers found
This review summarizes the state of evidence for cannabis-based treatments in epilepsy, focusing on the two main phytocannabinoids: cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC).
The clinical need is real: roughly 30% of epilepsy patients have seizures that resist available medications. CBD has the strongest evidence base, anchored by the FDA-approved Epidiolex for Dravet syndrome and Lennox-Gastaut syndrome. THC also has demonstrated anticonvulsant properties, though its psychoactive effects complicate its clinical use.
The review traces the evidence from early animal studies through to modern clinical trials, documenting how the understanding of cannabis for epilepsy has evolved over the past few decades. The authors note that despite growing evidence, many clinicians and regulatory bodies remain reluctant to prescribe or approve cannabis-based medicines for epilepsy patients.
The gap between evidence and access is a central theme. Patients who might benefit from cannabis medicines often can't get them through standard medical channels, leading some to seek unregulated products—which raises its own safety concerns (see RTHC-00150 on unapproved CBD products in children).
Why it matters
For the 30% of epilepsy patients with treatment-resistant seizures, the stakes are high—uncontrolled seizures carry risks of injury, cognitive decline, and sudden death. Cannabis-based medicines represent one of the few genuinely novel approaches in a field where most drugs work through similar mechanisms. Understanding the evidence base helps patients and clinicians make informed decisions.
The numbers in context
~30% of epilepsy patients have treatment-resistant seizures. CBD (Epidiolex) is FDA-approved for Dravet syndrome and Lennox-Gastaut syndrome. Both CBD and THC have demonstrated anticonvulsant properties in clinical studies.
How the study worked
Narrative review of the clinical evidence for cannabidiol and THC in epilepsy, covering preclinical studies, clinical trials, and regulatory context.
Who was studied
Review of clinical evidence related to cannabis use in epilepsy treatment.
What this study cannot tell us
Narrative reviews reflect the authors' selection of evidence and may not be comprehensive. The review appears to take an advocacy-oriented perspective (calling for more access), which may influence how the evidence is presented. Some of the clinical evidence is from open-label trials without placebo controls.
How to read the evidence
Narrative review summarizing a range of clinical evidence from animal studies to RCTs—useful for overview but limited by the authors' evidence selection.
When this study was published
Published in 2025 with current regulatory and clinical context.
The bigger picture
This review provides clinical context for the preclinical work in RTHC-00160 (carvone-derived CBD analogues showing enhanced anti-seizure effects in mice). Together, they illustrate the two tracks of cannabinoid epilepsy research: refining the clinical use of existing plant-derived cannabinoids and developing next-generation synthetic variants. The access barrier issue also connects to broader medical cannabis policy discussions (RTHC-00161 on medical marijuana laws and prescribing patterns).
Replication
Not stated in abstract.
Funding
Not reported in abstract.
Conflicts of interest
Not reported in abstract.
Questions still open
- Would wider access to pharmaceutical-grade CBD reduce patients' reliance on unregulated products? Are there epilepsy subtypes beyond Dravet and Lennox-Gastaut that would benefit from CBD? What role, if any, should THC play in epilepsy treatment given its psychoactive effects?
Read the original research
Medical Cannabis and Epilepsy: The Evidence.
British journal of hospital medicine (London, England : 2005), 86(11), 1-20
The British Journal of Hospital Medicine is a reputable publication focused on clinical practice and hospital medicine.
Citation
Kaur, Varinder; Deacon, Hannah; Barnes, Michael Philip; Nutt, David John. (2025). Medical Cannabis and Epilepsy: The Evidence.. British journal of hospital medicine (London, England : 2005), 86(11), 1-20. https://doi.org/10.12968/hmed.2024.0903
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