I don't think that's a meaningful question. One could go back a couple of centuries, before germ and virus theory was developed, and ask the same thing about p

I don't think that's a meaningful question. One could go back a couple of centuries, before germ and virus theory was developed, and ask the same thing about physical illnesses. It would be more accurate IMO to say that we're getting a better understanding of traits and characteristics of the human mind, some of which we currently have reason to believe are disorders, and are getting better at detecting those traits/characteristics.