MENTAL ILLNESSES HAVE confused and troubled humankind for thousands of years. Ancient historical records show them to be a persistent feature of the human condition. References to mental disorders can be found in the ancient writings of people in the Middle East, Greece, Rome, India, and China.

Ancient civilizations developed labels for people whose behavior was viewed as extremely unusual, making no sense in terms of external reality. A New Testament reference to mental illness in the Gospel of Luke says that "unclean spirits" came out of a man called "Legion" and were placed in swine, who then died. Legion is called a "demoniac," and the word "demons" has come to stand for madness or emotional struggles. The Egyptians said that a mentally ill person was "not in his right mind" or "smitten with madness." Greeks used phrases...