Justice committee  Yes. As THC breaks down in the body.... THC may hang around for a long time in fat cells and so forth, but it also creates a bunch of metabolites downstream that may or may not have different time courses. Some things may go away after a couple of hours. In cannabis right now we keep focusing on THC.

Justice committee  One thing we're trying to do—again, we have close collaboration with the DREs in California—is take the measures they think have the best possibility for being accurate detectors of cannabis-related impairment and doing further validation. There are some good studies out there in the field looking at how they relate to impaired drivers, one of which I showed, but there aren't really any blind clinical trials to say, if you don't give someone cannabis and you do these tests, how well do they do, and how well do the officers detect those people who are impaired or not?

Justice committee  That was someone else's study. In our study we're up to 13.4%. We're limited to what NIDA can provide.

Justice committee  It's getting better, but we're still behind the curve. Most studies you'll see were done with 6% THC. Right now they're up to 13%, which is what we're using. On average, drugs confiscated in America were about 12% to 15%. If you go to dispensaries, what they're putting out is around 30%.

Justice committee  I just do research, so we just see people in the lab. Perhaps the officer could comment on his own experience, but certainly, talking DREs, etc., the people they stop think they do better.

Justice committee  I certainly have heard a number of anecdotal comments like that, and I hope they're in the minority because it's unlikely to improve your driving. That said, there are some people who have anxiety and so forth, and maybe at a low dose there may be some benefit, but I certainly would not argue that it is something that would improve your driving.

Justice committee  Unfortunately, you really have to separate. The action is not in the blood, so unlike where there's this nice correlation—I'm sure people have said here—with alcohol, it's not the same with cannabis. It gets really complex because chronic users will have chronic levels in their blood.

Justice committee  Thank you. Good evening. I appreciate the opportunity to share some information as you consider Bill C-46, an act to amend the Criminal Code. I'm Tom Marcotte. I'm a professor of psychiatry at the University of California San Diego, and co-director of the University of California Center for Medicinal Cannabis Research.