Robert Spitzer, 83, a psychiatrist who played a leading role in establishing agreed-upon standards to describe mental disorders and eliminating homosexuality's designation as a pathology, died of heart problems Friday in Seattle, said his wife, Janet Williams, a Columbia University professor emerita.

Dr. Spitzer's work on several editions of the Diagnostic and Statistical Manual of Mental Disorders, or the D.S.M., defined all of the major disorders "so all in the profession could agree on what they were seeing," said Williams, who worked with him on D.S.M.-III, which was published in 1980.

Dr. Spitzer came up with agreed-upon definitions of mental disorders by convening meetings of experts in each diagnostic category and taking notes on their observations, the New York Times reported.

Allen Frances, a professor emeritus of psychiatry at Duke University and editor of a later edition of the manual, told the Times that Spitzer "was by far the most influential psychiatrist of his time."

Gay-rights activists credit Dr. Spitzer with removing homosexuality from the list of mental disorders in the D.S.M. in 1973. He decided to push for the change after he met with gay activists and determined that homosexuality could not be a disorder if gay people were comfortable with their sexuality.

In 2012, Dr. Spitzer publicly apologized for a 2001 study that found so-called reparative therapy on gay people can turn them straight if they really want to do so. He told the Times that he concluded the study was flawed because it simply asked people who had gone through reparative therapy if they had changed their sexual orientation. - AP