We want to know its safety. We want to know it's not going to kill people or give them cancer.
With medical cannabis, we need to be more patient, because it's very difficult to assess it in the same way. My answer to you is that there is ample preclinical science to make us believe.... There are thousands of studies on animals, and cellular and biological sciences, molecular studies and so on to tell us that cannabis is safe. We have historical evidence that tells us it's safe. It was used as a medicine for hundreds of years throughout Europe and North America and other parts of the world as a drug much as we know it, only in tincture form.
Currently, we have observational studies. We have a variety of smaller studies. New ones are under way, and you can get preliminary reports on those that tell you both that cannabis has relatively few serious side effects, which are easily managed, and that it is very efficacious, very effective, in a great number of treatments and for symptom relief.
The doctors who speak against it are entirely unfamiliar with the observational studies, or they discredit them quickly. A great deal of the negative papers published on cannabis—I know, because I've been through damn near all of them—are rife with bias. Bias permeates our society—bias around cannabis in particular—which is religious, cultural, political or social. We all know that, and you've probably heard from a number of people, officially and unofficially, who have this bias.
In the same way, there are people with biases in favour of cannabis—cannabis can do no wrong and it fixes everything. We have to discount those people too.