Sigmund Freud created sound scientific and medical theories that are still studied today. Freud was a neurologist who proposed many distinct theories in psychiatry, all based on the method of psychoanalysis. Some of its key concepts include the ego/superego/id, free association, trauma/fantasy, dream interpretation, jokes, and the unconscious. “Freud remained a determinist throughout his life, believing that all vital phenomena, including psychological phenomena such as thoughts, feelings and fantasies, are strictly determined by the principle of cause and effect” (Storr, 1989, p.2). Through the discussion of these central concepts, Freud's psychoanalytic theory becomes clear as to how he interpreted human character. Freud believed that human nature is fundamentally deterministic and depends largely on the unconscious. Irrational forces and unconscious motivations drive the human mind toward unique conduct and performance. Freud believed that the choices we make are determined by biological and instinctive drives. The goals of instincts are survival and aggression. In the field of psychiatry, Freud based his type of psychoanalytic therapy on the cure of mental illnesses. Freud's work treating mental patients was based on a disease called hysteria. A popular case that Freud began the majority of his work on is the Anna O. case. She suffered from many symptoms due to repressed ideas that apparently had no physical cause. Repression is a way of excluding unconscious desires, wishes or unpleasant memories in the conscious mind by retaining them in the unconscious mind. “According to Freud, repressed ideas often retained their power and were then expressed without the patient's knowledge. By ps...... middle of article ...... refuted or modified by today's psychologists, however its impact will always remain strong. His thoughts on human behavior were profound and original, making his techniques for treating psychological illnesses innovative. His use of self-awareness for unconscious thoughts was a smart approach for his time. “The principles of treatment set forth by Freud were very different from those followed by conventional physicians in the practice of medicine and must have seemed revolutionary before the First World War when they were formulated” (Storr, 1989, p. 95) . The way modern psychotherapy and forms of psychoanalysis are conducted today is based on Freud's procedure (Storr, 1989, p. 95). Works Cited “Psychoanalysis”. Compton's by Britannica, v 6.0. January 27, 2009. Storr, A. (ed.). (1989). Freud. Oxford: Oxford University Press.