I have a nephew who is schizophrenic. His father (my brother) is a psychiatrist. My nephew is not a genius, but he did graduate from a university with high honors. Then he started aquiring guns. Lots of them. My son shared an apartment with him and found a diary in which he talked about taking people with him. He listed the people he would take with him. He never hurt anyone, but his behavior led to a divorce, a lot of family turmoil, and a lot of pain. He's medicated now and doing ok, but he can't hold a steady job. He tutors children.
There is nothing more disturbing than a brain that doesn't work right. My nephew had the same initial response to medication as depicted in Beautiful Mind. It wrecked his ability to concentrate, he hated it, and refused to take the meds. I understand it is rare to be able to come to grips with a dual reality, to function in the "real" and to stop paying attention to the other "real" world. They are both equally compelling to the victim.
I don't have that direct an experience with this. I have heard similar things from relatives of schizophrenics.
One proble is though, there is some woman that keeps advertising on the radio things like "You can always control things that happen to you, but you can control how you feel about it." Of course, those who are depressed (or have other problems) simply cannot control their feelings.