I don't understand the third question, how is it possible for stigma to exist when a student achieves a certain number of grades when applying to universities, and they wouldn't know at all unless you tell them. Also stigma surrounding mental illness exists (sadly) pretty much everywhere, I don't think it's going to be significant enough a factor to prevent someone from applying to pursue higher education. I picked 1 in 50 just because most people when they've aged they realise they need to seek support actively in order to do well with their degree, but the other half may still not be willing because they are so afraid. As far as I'm concerned nothing is done at universities to encourage people to open up about themselves.