Alfred Adler (February 7, 1870 - May 28, 1937) was an Austrian medical doctor, psychotherapist, and founder of the school of individual psychology. He was a contemporary of Sigmund Freud, and was invited by him to join the Vienna Psychoanalytic Society, a group that discussed current thoughts in psychiatry. He disagreed with Freud's theory that mental disorders had their roots in sexual traumas, and further disagreed with the sexual emphasis in Freud's dream interpretations. In 1911, he left Freud's group and formed his own school. In his book The Neurotic Constitution (1912) he outlined his theory of "Individual Psychology": looking at a person as a whole rather than dividing them into smaller pieces. He also introduced the concept of an inferiority complex. He died suddenly in 1937 at the age of 67. While walking down a street, in Aberdeen, Scotland, he was seen to collapse and lie motionless on the sidewalk. The autopsy performed determined his death was caused by a degeneration of the heart muscle.