That's a huge topic. It might be something you might like to ask colleagues at the Centre for Addiction and Mental Health to talk about because there are specialists there. Some of it is their loss of status because Canada accepts people on the basis of being highly qualified, but when they get here, they often can't work in the fields in which they've qualified. So they go down the social scale. A lot of immigrants are willing to accept that in exchange for the benefits of coming to Canada, but it is also a big change. So psychologically there are some issues.
Then, of course, there's the lifestyle and dietary changes that occur, which can also have their toll. It's quite a complex question. For my part, it was an observation that this is the case, and that we were getting healthy people coming here. We shouldn't be thinking of immigrants as being unhealthy people. If you want an in-depth account of why that's the case, I would refer you to colleagues at CAMH.