A theorist who postulated stages of infancy, childhood, the juvenile era, preadolescence, early adolescence, and late adolescence in a theory known as the psychiatry of interpersonal relationships.

• A. Erik Erikson
• B. Sigmund Freud
• C. Harry Stack Sullivan
• D. Carl Jung

Answer: (C)

This question centers on a development theory that ties personality growth to interpersonal relationships across childhood into adolescence. The stages described—infancy through late adolescence—come from Harry Stack Sullivan, who framed psychiatry around how people relate to others and how those interpersonal needs shape personality. Sullivan’s view was that mental health arises from satisfying social needs and that development unfolds through distinct social eras, culminating in late adolescence with more complex peer and dating relationships. This focus on interpersonal dynamics as the engine of psychological development is what sets his work apart. Erik Erikson emphasizes psychosocial crises across the lifespan, Freud outlines psychosexual stages, and Jung proposes analytic psychology with archetypes, but none centers the same “psychiatry of interpersonal relationships” and these stage labels.