I think its down to it being more recognised now in this era instead of being ignored perhaps. Or its just on a rise due to change of what is defined as a mental illness?
None of the reasons you suggest though.
Also there seem to be alot of very depressed/anxious/unstable students these days due to the exam pressures. On the student forums there are quite a few people having break downs due to working too hard, rather than not at all
