[1] Having studied therapists Sigmund Freud, Adolf Meyer, and William Alanson White, he devoted years of clinical and research work to helping people with psychotic illness.
[2] Sullivan was a child of Irish immigrants and grew up in the then anti-Catholic town of Norwich, New York, resulting in a social isolation that may have inspired his later interest in psychiatry.
He attended the Smyrna Union School, then spent two years at Cornell University from 1909,[3] receiving his medical degree in Chicago College of Medicine and Surgery in 1917.
Along with Clara Thompson, Karen Horney, Erich Fromm, Otto Allen Will Jr., Erik H. Erikson, and Frieda Fromm-Reichmann, Sullivan laid the groundwork for understanding the individual based on the network of relationships in which they are enmeshed.
The resulting inaccuracies in judgment Sullivan termed parataxic distortion, when other persons are perceived or evaluated based on the patterns of previous experience, similar to Freud's notion of transference.
[10] Although some contemporaries and historians have regarded Inscoe as an adopted son, the biography of his colleague Helen Swick Perry mentions the relationship, suggesting that close friends were aware they were partners.