Psychoanalysis is a set of psychological and psychotherapeutic theories and associated techniques, created by Austrian physician Sigmund Freud and stemming partly from the clinical work of Josef Breuer and others. Over time, psychoanalysis has been revised and developed in different directions. Some of Freud's colleagues and students, such as Alfred Adler and Carl Jung, went on to develop their own ideas independently. Freud insisted on retaining the term psychoanalysis for his school of thought, and Adler and Jung accepted this. The Neo-Freudians included Erich Fromm, Karen Horney, and Harry Stack Sullivan.