This undated photo provided the Spitzer family shows Dr. Robert Sptizer, a psychiatrist who played a leading role in establishing agreed-upon standards to describe mental disorders and eliminating homosexuality's designation as a pathology. Spitzer died Friday, Dec. 25, 2015, in Seattle. He was 83. (Brian Chapman/Courtesy Spitzer family via AP)

Dr. Robert Spitzer—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 Friday in Seattle. He was 83.

Spitzer died of heart problems, said his wife, Columbia University Professor Emerita Janet Williams.

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 and became a best-selling book.

"That was a major breakthrough in the profession," she said.

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

"Rather than just appealing to authority, the authority of Freud, the appeal was: Are there studies? What evidence is there?" Spitzer told the New Yorker magazine in 2005. "The people I appointed had all made a commitment to be guided by data."

Dr. 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 activists and determined that homosexuality could not be a disorder if gay people were comfortable with their sexuality.

At the time of the psychiatric profession's debate over homosexuality, Dr. Spitzer told the Washington Post: "A medical disorder either had to be associated with subjective distress—pain—or general impairment in social function."

Dr. Jack Drescher, a gay psychoanalyst in New York, told the Times that Spitzer's successful push to remove from the list of disorders was a major advance for gay rights. "The fact that gay marriage is allowed today is in part owed to Bob Spitzer," he said.

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 in 2012 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.

"As I read these commentaries (about the study,) I knew this was a problem, a big problem, and one I couldn't answer," Dr. Spitzer told the Times. "How do you know someone has really changed?"

Dr. Spitzer and his wife moved to Seattle from New Jersey this year.