Robert Spitzer, an influential US psychiatrist who helped set up standards for the diagnosis of mental disorders and is credited with seeing homosexuality removed from the list of disorders, has died at age 83, US media reported.
Spitzer died on Christmas Day in the West Coast city of Seattle from complications of heart disease, his wife Janet Williams told The New York Times. He also suffered from Parkinson's disease.
In the 1970s, Spitzer played a crucial role in revising the Diagnostic and Statistical Manual of Mental Disorders (DSM), seen as the profession's main diagnostic guide.
His contributions to several editions of the DSM are seen as revolutionary, as he helped redefine many of the behaviors categorized as disorders, using stringent standards, rather than basing the classifications on Freudian analysis.
Spitzer was seen as the manual's guardian for two decades.
The award-winning psychiatrist worked at Columbia University in New York until 2003, when he retired.
"Bob Spitzer was by far the most influential psychiatrist of his time," Allen Frances, a professor emeritus of psychiatry at Duke University and editor of a later edition of the DSM, told the Times.
Homosexuality, which until the 1970s was listed as a mental disorder in the DSM, was one of the focuses of Spitzer's research.
He decided to push for the change after meeting with gay rights activists, concluding that if gays and lesbians were comfortable with their sexuality, it could not be a disorder.
Jack Drescher, a gay psychoanalyst working in New York, told the Times: "The fact that gay marriage is allowed today is in part owed to Bob Spitzer."
But Spitzer sparked controversy in 2001 when he published a study that described a "reparative" therapy to alter homosexual behavior. Gay activists cried foul, and he apologized in 2012, saying it was the only thing in his career that he regretted.
Spitzer is survived by his wife and five children.