Sigmund Freud is considered the founder of psychoanalytic theory and the father of psychodynamics, which is a theoretical perspective on thinking and behavior that emphasizes the role of the unconscious mind. Freud developed his theory of the psyche through his work with patients suffering from mental disorders such as hysteria and neurosis. He believed that the unconscious mind is the source of many of the conflicts that arise in the psyche and that these conflicts are the root cause of mental disorders.

Psychodynamic theory proposes that the psyche is divided into three parts in "dynamic" relations with each other: the id, the ego, and the superego. The id is the unconscious part of the psyche that is driven by the "pleasure principle," representing the instincts and impulses. The ego is the conscious part of the psyche that is driven by the "reality principle," representing the rational and logical self. The superego is the moral part of the psyche that is driven by the "ideal principle," representing the conscience. These three parts of the psyche interact with one another, and Freud thinks that the conflicts that arise between them are the source of many mental disorders.