Epilepsy and Cannabis: A Literature Review

Summary & key facts

This paper looked over past studies about using the cannabis plant to treat epilepsy, a brain condition that causes repeated seizures. About one-third of people with epilepsy do not get control from usual medicines. Older small studies with fewer than 15 people found little benefit from cannabis products. More recent, bigger studies with over 100 people found that cannabidiol, or CBD (a non-psychoactive part of cannabis), was linked to fewer seizures when added to regular epilepsy medicines. Side effects from CBD were usually mild, though some people had liver-related changes that often got better with continued use or lower doses. It is still unclear whether CBD itself stops seizures or mainly helps existing epilepsy drugs work better.

Key facts:

• Epilepsy is common worldwide and about one-third of people with epilepsy keep having seizures despite taking standard medicines.
• The cannabis plant contains two main active parts: THC, which causes the high, and CBD, which does not cause a high and is thought to be safer for seizures.
• Many early clinical studies had very few participants (fewer than 15 people) and did not show clear seizure reduction with cannabis.
• More recent studies that included over 100 people showed that adding CBD was linked to a meaningful drop in how often seizures happened.
• Most trials tested CBD alongside existing epilepsy medicines, so researchers do not yet know if CBD alone stops seizures or if it boosts other drugs.
• Reported side effects from CBD were generally mild, but some people showed higher liver enzymes; those effects often improved when CBD was continued or the dose was lowered.
• Researchers say future studies should look at whether CBD helps seizures from specific causes, like after a head injury or a stroke.

Abstract

Epilepsy is considered to be one of the most common non-communicable neurological diseases especially in low to middle-income countries. Approximately one-third of patients with epilepsy have seizures that are resistant to antiepileptic medications. Clinical trials for the treatment of medically refractory epilepsy have mostly focused on new drug treatments, and result in a significant portion of subjects whose seizures remain refractory to medication. The off-label use of cannabis sativa plant in treating seizures is known since ancient times. The active ingredients of this plant are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), the latter considered safer and more effective in treating seizures, and with less adverse psychotropic effects. Clinical trials prior to two years ago have shown little to no significant effects of cannabis in reducing seizures. These trials seem to be underpowered, with a sample size less than 15. In contrast, more recent studies that have included over 100 participants showed that CBD use resulted in a significant reduction in seizure frequency. Adverse effects of CBD overall appear to be benign, while more concerning adverse effects (e.g., elevated liver enzymes) improve with continued CBD use or dose reduction. In most of the trials, CBD is used in adjunct with epilepsy medication, therefore it remains to be determined whether CBD is itself antiepileptic or a potentiator of traditional antiepileptic medications. Future trials may evaluate the efficacy of CBD in treating seizures due to specific etiologies (e.g., post-traumatic, post-stroke, idiopathic).

Topics

Cannabis and Cannabinoid Research Epilepsy research and treatment Neuroscience and Neuropharmacology Research

Categories

Health Sciences Medicine Pharmacology

Tags

Adverse effect Cannabidiol Cannabinoid Cannabis Clinical trial Effects of cannabis Epilepsy Internal medicine Medicine Pediatrics Pharmacology Psychiatry Receptor Tetrahydrocannabinol

Substances

Cannabis