The American psychiatrist Harry Stack Sullivan (1892-1949) based his approach to mental illness primarily upon interpersonal theory.

Harry Stack Sullivan, born on Feb. 21, 1892, in the farming community of Norwich, N.Y., was the only surviving child of a poor Irish farmer. His childhood was apparently a lonely one, his friends and playmates consisting largely of the farm animals. His mother, who was sickly, was unhappy with the family's poor situation, and is reported to have shown her son little affection. These personal experiences seem to have had a marked effect on Sullivan's professional views in later life.

Sullivan took his medical degree in 1917 at the Chicago College of Medicine and Surgery. In 1919 he began working at St. Elizabeth's Hospital in Washington, D.C., with William Alanson White, an early American psychoanalyst. Clinical research at Sheppard and Enoch Pratt Hospital occupied a portion of Sullivan's life, as did an appointment in the University of Maryland's School of Medicine. In 1936 he helped establish the Washington School of Psychiatry. In later life he served as professor and head of the department of psychiatry in Georgetown University Medical School, president of the William Alanson White Psychiatric Foundation, editor of Psychiatry, and chairman of the Council of Fellows of the Washington School of Psychiatry.

Sullivan's approach to psychiatry emphasized the social factors which contribute to the development of personality. He differed from Sigmund Freud in viewing the significance of the early parent-child relationship as being not primarily sexual but, rather, as an early quest for security by the child. It is here that one can see Sullivan's own childhood experiences determining the direction of his professional thought.

Characteristic of Sullivan's work was his attempt to integrate multiple disciplines and ideas borrowed from those disciplines. His interests ranged from evolution to communication, from learning to social organization. He emphasized interpersonal relations. He objected to studying mental illness in people isolated from society. Personality characteristics were, he felt, determined by the relationship between each individual and the people in his environment. He avoided thinking of personality as a unique, individual, fixed unchanging entity and preferred to define it as a manifestation of the interaction between people.

On Jan. 14, 1949, while returning from a meeting of the executive board of the World Federation for Mental Health, Sullivan died in Paris. He was buried in Arlington National Cemetery.