[3] In the course of his career, Bowman conducted pioneering work on the psychiatric effects of alcohol, drugs, and sexuality.
He testified at the trials of Nathan F. Leopold and Richard Loeb for the murder of Robert Franks in 1924 as well as in many other celebrated cases.
During his career, Bowman was the chief medical officer at the Boston Psychopathic Hospital; an assistant professor of psychiatry at Harvard Medical School (1921–1936); the chief of psychiatry at Bellevue Hospital (1936–1941); a professor of psychiatry at New York University Medical College (1936–1941); the first chairman and director of the Langley Porter Psychiatric Institute (1941–1956); and a professor at the University of California, Berkeley.
He was also the head of the Laguna Honda Psychiatric Hospital in San Francisco (1941–1967) [3] As the retiring president of the American Psychiatric Association in 1946, he made headlines when he predicted that 10 million people in the United States would at some time in their lives require hospitalization for mental disorders.
Bowman was Head of the Department of Psychiatry at Bellevue Hospital in New York City when Dr. Allen Gregg (Director of the Rockefeller Foundation) asked him to participate in an alcoholism study he had been preparing.
[7] In 1953, in "The Problem of Homosexuality," co-authored with Bernice Engle, he argued for multiple causes, including genetics, but proposed that castration be studied as a cure.
[8] However, in 1961 he appeared in the television documentary The Rejected presenting the viewpoint that homosexuality is not a mental illness and should be legalized.