- Freud's psychoanalytic theory views personality as being divided into the id, ego, and superego. The id operates based on the pleasure principle, the ego balances the demands of the id and reality, and the superego incorporates moral standards.
- Freud also proposed psychosexual stages of development from infancy through young adulthood and the concepts of the conscious, preconscious, and unconscious.
- Sullivan's interpersonal theory emphasizes that personality develops through relationships and interactions with others. It focuses on reducing anxiety and achieving interpersonal security.