thinking too much is potentially harmful to your health

The Medieval scholastics called it 'God,' the ancient Greeks called it 'infinity.' Cantor in the late 19th century devised a mathematical deity/infinity proof, partly with his set theory and related axioms, and the strain caused him to declare himself Gods messenger and then he killed himself.
Kurt Godel proposed an incompleteness theorem which shows us the ultimate limitation of human knowledge- which means that ultimate truth must be received through intuition- then he starved himself to death, because he thought everyone was trying to poison him.

Lucretius, about 100 BC, came up with evolutionary and atomic theory, and in a manic-depressive fit killed himself.
Aristotle, sick and old and implicated in a plot to kill his former pupil, Alexander, hanged himself in 322 BC.
Sigmund Freud killed himself with an overdose of morphine.