Sigmund Freud: An Austrian neurologist who is widely regarded as the founder of psychoanalytic theory. He developed groundbreaking concepts such as the unconscious mind, defense mechanisms, and psychosexual stages.
Psychoanalytic Theory: A psychological approach developed by Sigmund Freud that emphasizes the role of unconscious processes in shaping human behavior and personality.
Psychodynamic Theory: A broader term used to describe theories influenced by Freud's work that focus on unconscious processes and early childhood experiences in understanding human behavior.