The ancient Greeks had long thrown cannabis onto hot coals to aid in relaxation, but it was centuries later that Dr. William Brooke O’Shaughnessy became the first to introduce the plant to the European medical community as a potential medicine.

In his research in the 19th century, O’Shaughnessy found that cannabis had great value as a sedative and an anti-convulsant. He used it to relieve the pain of rheumatism (arthritis) and quell muscle spasms in patients. By validating the centuries-old folk uses of cannabis through a medical lens, O’Shaughnessy popularized the therapeutic uses of the plant in medical papers.

To read his 1843 scientific paper, On the Preparations of the Indian Hemp, or Gunjah: Cannabis Indica, is to marvel at how long the medical community has taken to validate some of his clinical findings. For example, he reports treating an infant with a severe seizure disorder with an alcohol extract of ‘hemp’ (gunjah or C. indica), which reduced her seizures significantly.

“The influence of the drug in allaying pain was equally manifest in all the memoirs referred to. As to the evil sequels so unanimously dwelt on by all writers, these did not appear to me so numerous, so immediate, or so formidable, as many which may be clearly traced to over-indulgence in other powerful stimulants or narcotics-viz, alcohol, opium, or tobacco.”

~ William B. O’Shaughnessy, MD

O’Shaughnessy concluded that the case studies he reported, “constitute the grounds of my belief that in hemp the profession has gained an anti-convulsive remedy of the greatest value.”

It would be 175 years before the medical community heeded his prescient claims and cannabis-derived medicines were on the legal market.

By the early 20th century, thousands of different cannabis medicines were being produced by close to 300 manufacturers in the West. These included unregulated patent medicines—some of which were dangerous—that were advertised with unsubstantiated and often fraudulent claims about their efficacy.

This caused the ire of American authorities, who implemented the Pure Food and Drug Act at the start of the 20th century, an action that set cannabis on the course to criminalization. In Canada, racism, propaganda, and scare-tactic journalism combined to influence the criminalization of cannabis, which was added to the Schedule of Restricted Drugs in 1923 under the Narcotics Drug Act Amendment Bill. These laws curtailed further research and prevented the application of medical cannabis throughout the century.

It was only in 2018 that the FDA in the United States approved its first cannabis-derived prescription drug. Epidiolex is a 100 mg/mL oral solution of cannabidiol used in the treatment of two forms of treatment-resistant epilepsy in children. Children with these disorders–called Dravet syndrome and Lennox-Gastaut syndrome–can suffer from multiple seizures every day. CBD has provided relief in many cases, reducing seizure frequency considerably. Given this, and the general interest in CBD as a therapeutic tool, there is a need for large quantities of this cannabinoid.

One good source of CBD that will soon be tapped is hemp, a variety of Cannabis sativa that contains only small amounts of THC. This lack of THC was one factor that allowed passage of the US Government’s Farm Bill in December 2018, which removed hemp from the Controlled Substances Act. Hemp can now be grown and processed in the US for any commercial purpose. This will substantially increase industrial hemp production and, consequently, the production of CBD oil. (In January, Canopy Growth received a New York State hemp licence and announced that it will establish U.S.-based commercial operations.)

The history of CBD as a therapeutic embraced by the medical profession appears to have come full circle from the work pioneered by O’Shaugnessy.

O’Shaughnessy WB. 1843. On the preparations of the Indian hemp, or Gunjah (Cannabis Indica). Provincial Medical Journal. 123:363-369.