"[I]f a healthy man lies in bed, let him do it without a rag of excuse; then he will get up a healthy man. If he does it for some secondary hygienic reason, if he has some scientific explanation, he may get up a hypochondriac."
- G.K. Chesterton. "On Lying in Bed" in Tremendous Trifles, 1909.
"In fact, psychologist Matthew Walker of the University of California, Berkeley, says that 'almost all psychiatric disorders show some problems with sleep.' But, he says that scientists previously believed the psychiatric problems triggered the sleep issues. New research from his lab, however, suggests the reverse is the case; that is, a lack of shut-eye is causing some psychological disturbances."
- Nikhil Swaminathan. "Can a Lack of Sleep Cause Psychiatric Disorders?" in Scientific American, October 23, 2007.