Watch below the wonderful BBC-4 documentary 'Dangerous Knowledge' (2008) about four great mathematicians (well, actually Boltzmann is rather a physicist than a mathematician):
Georg Cantor, Ludwig Boltzmann, Kurt Gödel and Alan Turing.
Cantor and Gödel went insane, Boltzmann and Turing committed suicide...so dangerous the pursuit of knowledge can be.
Part 1 of the documentary:
Part 2:
Part 3:
Part 4:
Part 5: