Fame
No doubt there have been some extremely famous psychiatrists throughout history. Topping the charts, with no competition, is Sigmund Freud. Sigmund is considered the father of psychoanalysis—he was a neurologist who became fascinated with the idea of taking what he knew of the brain and applying it to real people in real situations.
He was particularly intrigued by dreams, and by what they represented or revealed about the dreamer. Strangely, about ninety-five percent of them apparently had something to do with repressed sexual feelings about one's parents. Freud was one guy who had trouble keeping his mind out of the gutter. While most of his theories have been disproved, he remains the most important psychiatrist ever because he started the whole shebang.
Other famous psychiatrists include Carl Jung (pioneer in the field of analytical psychology), Elisabeth Kubler-Ross (author of the book Of Death and Dying), Oliver Sacks (whose book Awakenings was adapted to a film starring Robin Williams) and Lucy (who's famous for her dirt-cheap rates and sound advice).