“Cannabis as a smoked product, in my judgment, would not be a useful product simply because of the lack of standardization, the fact that it’s a smoked material: you can’t determine the dose, people smoke in different ways, plus the interaction of the many different components and degradation products, and the tars associated with smoked materials. So smoking is not a good delivery system.

However, cannabis as a plant that is rich in chemical components, would have potential for producing useful drugs, for example THC. Now THC in the oral preparation, it doesn’t seem to be doing the good job it should or was expected to. My personal view on the reason for this is the ‘first-pass effect.’ The material taken orally goes through the liver and is converted to the 11-hydroxy metabolite, which is 4-5 times more potent in terms of psychoactivity, before getting into the bloodstream, and the profile of these two drugs is quite different.”