Cannabis and Epilepsy: A History Spanning Millennia

From ancient pharmacopeias to a modern FDA-approved medicine.

The use of cannabis to treat seizures is not a modern idea. It has a long and cross-cultural history — and that history runs all the way to a landmark clinical trial and the first cannabis-derived medicine approved by the FDA. Here's how the story unfolded.

Ancient Roots

Cannabis appears in some of the world's oldest medical traditions. According to long-standing tradition, the Chinese emperor Shen Nung — a semi-legendary figure often called the father of Chinese medicine — included cannabis in an early pharmacopeia thousands of years ago, recommending it for a range of ailments. In ancient India, cannabis held a place in Ayurvedic medicine and is mentioned in the Atharvaveda, a text more than 3,000 years old, as one of several sacred plants used for healing.

The medieval Islamic medical tradition recognized cannabis as well. The influential Persian physician Avicenna, in his Canon of Medicine — a text that shaped medicine in both the Eastern and Western worlds for centuries — described cannabis among treatments for epilepsy and other conditions.

Cannabis Enters Western Medicine

Cannabis entered mainstream Western medicine largely through the work of Dr. William O'Shaughnessy, an Irish physician working in India. In the 1840s, he studied cannabis extensively and published influential work describing its therapeutic potential, including for seizures. Through the 19th and early 20th centuries, cannabis preparations were a recognized part of the Western medical toolkit.

That changed in the 20th century. Increasing regulation and criminalization — in the United States, notably the Marihuana Tax Act of 1937 — sharply restricted access to cannabis and curtailed research. Interest faded, even as anecdotal reports continued to suggest cannabis might have anticonvulsant properties.

A Scientific Turning Point

The identification of the endocannabinoid system in the early 1990s changed the picture. This signaling network — cannabinoid receptors and related molecules found throughout the body — helps regulate processes including mood, pain, and seizure activity. Its discovery gave researchers a biological explanation for how cannabinoids could affect the body, and renewed serious scientific interest in cannabis.

Then came a story that captured public attention. In the early 2010s, a young girl named Charlotte Figi, who had Dravet syndrome — a severe, treatment-resistant childhood epilepsy — was treated with a high-CBD cannabis extract. Her family and doctors reported a dramatic drop in seizure frequency. Her case drew widespread media coverage and helped spark a wave of serious clinical research into CBD for epilepsy.

The Landmark Trial — and an Approved Medicine

That research produced rigorous evidence. In 2017, the New England Journal of Medicine published a landmark trial: a double-blind, placebo-controlled study of 120 children and young adults with Dravet syndrome, comparing a purified CBD oral solution against placebo alongside their standard treatment. The trial found that CBD reduced seizure frequency — the gold-standard kind of evidence that earlier, uncontrolled reports could not provide.

Studies like this one, including research in another severe epilepsy called Lennox-Gastaut syndrome, built the case that led to a historic milestone: in 2018, the FDA approved Epidiolex, a purified CBD medication, for the treatment of certain forms of epilepsy. It was the first cannabis-derived medicine the FDA had ever approved — turning thousands of years of traditional use, and decades of modern science, into a recognized prescription treatment.

Key reference: Devinsky O, Cross JH, Laux L, et al. Trial of Cannabidiol for Drug-Resistant Seizures in the Dravet Syndrome. New England Journal of Medicine, 2017;376(21):2011–2020. DOI: 10.1056/NEJMoa1611618.

This article is for general educational and historical information only and is not medical advice. Epilepsy is a serious condition — please consult a qualified healthcare professional regarding treatment, and do not change any prescribed medication without medical guidance.