Former New England Patriots' tight end Aaron Hernandez had a severe case of chronic traumatic encephalopathy (CTE), a degenerative brain disease associated with repeated head trauma. The finding was announced today in a press conference held by his lawyer, according to the New York Times.

CTE leads to progressive cognitive impairment and behavioral regulation problems—and it has notably been linked to depression, suicide, and impulsive and violent behavior.

Hernandez committed suicide in April while serving a life sentence for the 2013 murder of his friend. He was 27.

Dr. Ann McKee, chief of neuropathology at the VA Boston Healthcare System and director of the CTE Center at Boston University, examined Hernandez’s brain and made the CTE determination.

According to Jose Baez, Hernandez’s lawyer, Hernandez’s CTE was “the most severe case they had ever seen in someone of Aaron’s age.” The level of damage was said to be similar to that seen in football players with a median age of 67.

As the New York Times notes, Hernandez is just the latest player who committed suicide and was later found to have CTE, which is only diagnosed after death. Other players include Dave Duerson, Junior Seau, Andre Waters, Ray Easterling, and Jovan Belcher. Duerson and Seau committed suicide by shooting themselves in the chest, an apparent effort to ensure that researchers could examine their brains afterward. Hernandez hanged himself in his prison cell.

A string of other young football players have decided to retire early from professional play out of concern for developing CTE. That includes former Bengals' and Browns' wide receiver Andrew Hawkins and Baltimore Ravens’ offensive lineman John Urschel.

Baez has filed a lawsuit against the National Football League and the Patriots on behalf of Hernandez’s daughter. The suit alleges that the league and the team were “fully aware of the damage that could be inflicted from repetitive impact injuries and failed to disclose, treat, or protect him from the dangers of such damage.” The suit seeks unspecified damages.