From the WebMD Archives

Editor's Note:  On Nov. 9, Ann McKee, M.D., director of the Boston University Chronic Traumatic Encephalopathy Center, said that Hernandez's brain showed severe trauma not seen before in someone his age.  

Sept. 21, 2017 -- Former NFL player Aaron Hernandez was suffering from a brain disease common to football players when he died, doctors say.

Doctors from Boston University who examined his brain tissue after his death determined that Hernandez had stage 3 chronic traumatic encephalopathy (CTE). CTE is a kind of progressive deterioration of the brain caused by repetitive head injuries, such as concussions. Stage 4 is the most severe form.

CTE leads to chronic depression, aggression, explosive behavior, impulsivity, and short-term memory loss.

Specialists at Boston University who examined Hernandez’s brain found classic features of CTE, they said, including a buildup of tau protein in his frontal lobes.

Hernandez, 27, played for the New England Patriots. He was convicted in the 2013 killing of semi-pro football player Odin Lloyd and sentenced to life in prison. He killed himself in his jail cell earlier this year.

An attorney for his family said he had filed a federal lawsuit on behalf Hernandez’s daughter against the NFL and the Patriots.

Other athletes diagnosed with CTE after their deaths include wrestler Chris Benoit, who murdered his wife and son before killing himself in 2007; baseball player Ryan Freel, who killed himself in 2012; and linebacker Junior Seau, who also killed himself in 2012.