"A lot of these cases that end in suicide are precipitous -- they're not prolonged with the dragging out of symptoms," said Bailes.
He says that the majority of people who commit suicide are depressed, talk about it, exhibit warning signs, seek treatment and council, or go on antidepressants.
"But in CTE and suicides, as we saw with people like Dave Duerson" -- another former NFL player with neurodegenerative disease who committed suicide -- "and Junior Seau, those cases were without warning," said Bailes.
Duerson, a two-time Super Bowl champion, chose to shoot himself in the chest so that, as he requested in text messages to his family before he died, his brain could be studied for signs of CTE. Three months after his death neurologists at Boston University confirmed Duerson's brain showed "moderately advanced" evidence of CTE.
"While it's great to make the diagnosis at autopsy, the frustration was all the people were dead by that point," Bailes said. "In the very least, if we could find out who has a lot of this tau protein in their brain, you would think we'd have a chance to intervene."