Health committee  My findings are based on a comprehensive review of the empirical literature, on my expertise as a professor at UBC, where I teach the course on drugs and behaviour, and on my considerable experience in treating mental health and addiction.

Health committee  I can speak specifically to university students who we do research with at UBC. This is generally a high-performing group. Of those students, the rates of cannabis use are similar to what we see in the general Canadian population. We have about 35% to 40% who have used in the past year and maybe 5% to 10% who are fairly frequent users.

Health committee  That study was conducted at Harvard a number of years ago. Based on their sort of comprehensive neuropsych IQ tests, they didn't see any differences between the heavy users, the recently abstinent, and those who were never users.

Health committee  Unfortunately, that's not being done, to my knowledge. One thing you'll see running through the testimony and the research on medical cannabis is that it's incredibly difficult to conduct studies using cannabis, either administering it or clinical trials. There's so much research that remains to be done.

Health committee  Certainly, and I don't think anyone would advocate cannabis use for young people. The study that you referred to, the Dunedin study, is one of the studies where substantial concerns have been raised about confounds. With the criminalization of cannabis, we see people who are more likely to violate all kinds of rules using cannabis.

Health committee  Well, I think the good research remains to be done as far as the side-by-side efficacy of cannabis versus other anti-anxiety medications is concerned, but our reports from medical users and non-medical users indicate that cannabis does reduce their anxiety. It's one of the primary reasons that people use it.

Health committee  I'm familiar with the findings of acute cognitive effects of cannabis intoxication. I'm not familiar with the Ottawa pre-natal study that you refer to, but I am quite familiar with the literature on the cognitive effects of cannabis. My sense of the literature is that the effects are generally reversible following cessation of cannabis use and that they vary according to the user's familiarity with cannabis, so that when cannabis is administered to relatively naïve users we see more profound deficits and that with regular users there is tolerance of most of the cognitive effects.

Health committee  Well, not exactly. I think it reflects the confounding effects of people who use one or both.

Health committee  I don't know of any evidence to suggest that marijuana leads to increased suicide.

Health committee  No.

Health committee  Yes.

Health committee  So, yes.

Health committee  I am not a doctor or a pharmacist, no. A health care professional....

Health committee  Yes.

Health committee  Rather, I'm referring to the results of the study that showed that in people who used both cannabis and tobacco, compared to tobacco alone, we see worse outcomes among the tobacco users. It has to do with the increased stigmatization of tobacco use.