...the staff at my university, the Massachusetts Institute of Technology, and later all of Boston were behaving strangely towards me. ...I started to see crypto-communists everywhere. ...I started to think I was a man of great religious importance, and to hear voices all the time. I began to hear something like telephone calls in my head, from people opposed to my ideas. ...The delirium was like a dream from which I seemed never to awake.
I would not dare to say that there is a direct relation between mathematics and madness, but there is no doubt that great mathematicians suffer from maniacal characteristics, delirium and symptoms of schizophrenia.