"Many geniuses were partially insane, if not wholly insane; many geniuses lived on the borderline between sanity and insanity. Schopenhauer had many irrational fears and anxieties; fearing that people would misinterpret a trance as death and bury him alive, Schopenhauer ‘stipulated that his remains be left unburied beyond the usual time.’ Cézanne is another example of a genius who was partially insane. Cézanne experienced ‘chronic paranoia’; when his friends threw a party to celebrate his birthday, he left abruptly, thinking they were making fun of him. Gödel was so afraid of being poisoned that he stopped eating, and starved to death.
The genius lacks moderation. Dostoyevsky, for example, said, ‘I go to the ultimate limit everywhere and in everything; all my life long I have always approached the limit!’"
— L. James Hammond, from Conversations with Great Thinkers