SYRACUSE, N.Y. -- There's a number of symptoms that have been linked to CTE.
"Poor impulse control, depression … Confusion, memory loss, poor judgment," said Upstate Concussion Center Program Director Brian Rieger.
But at this stage in the game, experts can only connect the dots, as Rieger says, "in people who went on to be diagnosed post-mortem."
CTE: Chronic Traumatic Encephalopathy, three letters making headlines more and more over the past decade -- most recently with former New England Patriots tight end Aaron Hernandez, who was serving life in prison for murder. After his jail-cell suicide, the ex-NFL player's brain is expected to be donated to CTE research.
"I don't think we can automatically assume that football makes you that way,” Rieger said. “However, there's certainly the case that in some cases, people's behavior moved outside of the norm and they went on to have diagnosed CTE."
So then it's back to nature versus nurture.
"We don't want to jump to the conclusion that, ‘oh, that's a football player, that must be why this person engaged in violent behavior or why they became depressed.’ We don't have the ability to make those connections yet,” said Rieger.
But before you pull your child from a sport that they love, Rieger says to look again at the progress of safety in the game.
"In hockey, they've changed the age at which you can start checking to try to reduce the incidents of head trauma, and it's been effective,” said Rieger. “In football, they're trying to teach better tackling techniques."
Which is why, when Rieger hears from concerned parents, he opens the discussion.
"It's not black and white; it's a conversation,” said Rieger. “And we all need to educate ourselves with what we're learning, but until we have guidelines, we're guessing."