The compound that causes the psychoactive effects of cannabis is “tetrahydrocannabinol,” which is usually abbreviated THC. A second compound which is without psychoactive effects is “cannabidiol” — abbreviated CBD. CBD has medicinal effects but it doesn’t make you high.
Scientific research into the seizure-suppressing effects of the cannabinoids was pioneered by Karler and Turkanis at the University of Utah. Working in animals, they showed that CBD — which doesn’t make you high — was as good as THC at suppressing seizures. Small clinical trials by other researchers confirmed that CBD also stopped seizures in humans and didn’t make them high either. This line of research led to an international symposium in 1981, which summarized most of what we know today about the cannabinoids and epilepsy. Then, suddenly, this line of research stopped dead. Nothing more was heard for thirty years or so.
The University of Toronto enters the story at this point. At the University of Toronto, we had become interested in the anticonvulsant effects of CBD in the 1980s due to the work of Karler and Turkanis. We had wondered whether CBD would be effective in our animal model of complex partial seizures. Complex partial seizures — which are now called “dyscognitive” — are the most common sort of seizures in adults and are very hard to control with anticonvulsant drugs. We couldn’t access CBD at that time, however. The only legal source of CBD in Canada in the 1980s was the federal government, and the federal government could not provide any. We turned to other lines of research.
Some thirty years later, medical marijuana resurfaced in the news. It was brought to the forefront by parents of children with uncontrollable epilepsy who wanted something better to help their children. (This was somewhat similar to the rediscovery of the ketogenic diet by parents in the 1990s.) It was found that medical marijuana seemed to improve certain devastating forms of childhood epilepsy. This led to the production and testing of cannabis extracts by GW Pharmaceuticals in England — and to a series of clinical trials that are currently in progress.
At the University of Toronto, we became interested again. Since CBD was now available, we hoped to get on with the animal tests we had wanted to do in the 1980s. The major problem lay in getting the CBD, however. Although CBD doesn’t make you high, it is legally classed with THC, which does. We therefore had to go through all of the steps related to obtaining a “banned” drug for research purposes.
