– In 1936, Ernest Hemingway told a friend he'd never kill himself, the Charlotte Observer reports. The great author was dead by his own hand 25 years later. According to Smithsonian, Hemingway scholars have long blamed the writer's decade-long decline and eventual suicide on some combination of alcoholism and bipolar disorder. But a psychiatrist in North Carolina says the actual culprit is something more associated with modern football players than authors: CTE. Andrew Farah has been studying Hemingway for 20 years, Fox 8 reports. By reading Hemingway's letters, memoirs by his friends and family, and the FBI file on him, Farah was able to trace what he believes is the source of Hemingway's downfall: at least nine concussions. Those concussions came from boxing, car crashes, exploding shells during two world wars, and more. "His injuries and head traumas were frequent, random, and damaging," Farah writes in his newly published book, Hemingway's Brain. For example, following a plane crash that had likely already concussed him, Hemingway used his head to bash out a door and escape the plane. While we likely will never know for sure if Hemingway suffered from CTE, Farah says he showed symptoms in his final years, such as paranoia, anger, and violence. He also got worse following electroconvulsive therapy. "It didn't take long to connect the dots," Farah tells Smithsonian. He says he hopes his conclusion will allow the focus to shift from the "mythology" of Hemingway's death to the greatness of his work. (How sports destroyed a young man's brain.)