I don't mind the brain tumor theory because it's treatable. As long as he pulls through in the end I'm alright with it.
But I certainly don't want schizophrenia or drug addiction.

I seriously doubt we'll have a plot where we learn his mother is not his mother (same thing with his father).

I'm not going to theorize or get excited by this news. I was so disappointed by the results of Reid's storyline in the sixth season, I won't make the same mistake twice.
For all we know they are just going to confirm that it's stress related...(and I would prefer them to completely drop that storyline than that).