Chronic Traumatic Encephalopathy (CTE) is defined, by the Boston University CTE Center, as a degenerative brain disease caused in part by repeated traumatic injuries to the head as a result of both concussions and nonconcussive impacts. CTE was first described in 1928 by Dr. Harrison Martland when he described several boxers as having “punch drunk syndrome.” It wasn’t until 2005, more than 75 years later, that the first evidence of the disease was found by forensic pathologist Dr. Bennet Omalu when he autopsied former NFL player Mike Webster.
CTE can only be conclusively diagnosed post-mortem through an autopsy, leaving many athletes to suffer from its symptoms unchecked during their lives. Common symptoms include confusion, impaired judgment, and extreme mood swings with aggression. Many former players diagnosed with CTE had a history of violent behavior, with some even committing murder or suicide.
In recent years, suicide has been strongly linked to CTE, with at least 12 of the 35 deceased players having taken their own lives. A 2017 article in the Journal of the American Medical Association discovered signs of CTE in 110 out of 111 brains of deceased former NFL players. (Here are 33 athletes with famously bad tempers.)
To compile a list of professional football players whose deaths are at least partially attributable to CTE, 24/7 Tempo reviewed player profiles published by the Concussion Legacy Foundation and articles from Boston University’s CTE Center. Additionally, we examined archived news stories about deceased football players from sources such as ESPN, CNN, Sports Illustrated, NPR, and other online platforms.
Here are NFL legends diagnosed with CTE:
Aaron Hernandez (1989-2017)
- NFL teams: New England Patriots
- Position: Tight end
- Years playing in the NFL: 2010-2012
- Cause of death: Suicide by hanging
Adrian Robinson (1989-2015)
- NFL teams: Pittsburgh Steelers, Philadelphia Eagles, Denver Broncos, San Diego Chargers, Washington Redskins
- Position: Linebacker
- Years playing in the NFL: 2012-2015
- Cause of death: Suicide by hanging
Andre Waters (1962-2006)
- NFL teams: Philadelphia Eagles, Arizona Cardinals
- Position: Defensive back
- Years playing in the NFL: 1984-1995
- Cause of death: Self-inflicted gunshot wound
Bubba Smith (1945-2011)
- NFL teams: Baltimore Colts, Oakland Raiders, Houston Oilers
- Position: Defensive lineman
- Years playing in the NFL: 1967-1976
- Cause of death: Drug overdose
Chris Henry (1983-2009)
- NFL teams: Cincinnati Bengals
- Position: Wide receiver
- Years playing in the NFL: 2005-2009
- Cause of death: Car accident
Colt Brennan (1983-2021)
- NFL teams: Washington Redskins, Oakland Raiders
- Position: Quarterback
- Years playing in the NFL: 2008-2010
- Cause of death: Drug overdose
Cookie Gilchrist (1935-2011)
- NFL teams: Buffalo Bills, Denver Broncos, Miami Dolphins
- Position: Fullback
- Years playing in the NFL: 1962-1967
- Cause of death: Bladder cancer
Daniel Te’o-Nesheim (1987-2017)
- NFL teams: Philadelphia Eagles, Tampa Bay Buccaneers
- Position: Linebacker
- Years playing in the NFL: 2010-2013
- Cause of death: Lethal mixture of pills and alcohol
Dave Duerson (1960-2011)
- NFL teams: Chicago Bears, New York Giants, Phoenix Cardinals
- Position: Safety
- Years playing in the NFL: 1983-1993
- Cause of death: Self-inflicted gunshot wound
Demaryius Thomas (1987-2021)
- NFL teams: Denver Broncos, Houston Texans, New England Patriots, New York Jets
- Position: Wide receiver
- Years playing in the NFL: 2010-2019
- Cause of death: Seizure
Earl Morrall (1934-2014)
- NFL teams: San Francisco 49ers, Pittsburgh Steelers, Detroit Lions, New York Giants, Baltimore Colts, Miami Dolphins
- Position: Quarterback
- Years playing in the NFL: 1956-1976
- Cause of death: Complications from Parkinson’s disease
Frank Gifford (1930-2015)
- NFL teams: New York Giants
- Position: Running back
- Years playing in the NFL: 1952-1960, 1962-1964
- Cause of death: Natural causes
Fred McNeill (1952-2015)
- NFL teams: Minnesota Vikings
- Position: Linebacker
- Years playing in the NFL: 1974-1985
- Cause of death: Lou Gehrig’s disease
Greg Clark (1972-2021)
- NFL teams: San Francisco 49ers
- Position: Tide end
- Years playing in the NFL: 1997-2001
- Cause of death: Self-inflicted gunshot wound
John Grimsley (1962-2008)
- NFL teams: Houston Oilers, Miami Dolphins
- Position: Linebacker
- Years playing in the NFL: 1984-1993
- Cause of death: Accidental gunshot wound
John Mackey (1941-2011)
- NFL teams: Baltimore Colts, San Diego Chargers
- Position: Tight end
- Years playing in the NFL: 1963-1972
- Cause of death: Dementia
Jovan Belcher (1987-2012)
- NFL teams: Kansas City Chiefs
- Position: Linebacker
- Years playing in the NFL: 2009-2012
- Cause of death: Self-inflicted gunshot wound
Junior Seau (1969-2012)
- NFL teams: San Diego Chargers, Miami Dolphins, New England Patriots
- Position: Linebacker
- Years playing in the NFL: 1990-2009
- Cause of death: Self-inflicted gunshot wound
Justin Strzelczyk (1968-2004)
- NFL teams: Pittsburgh Steelers
- Position: Offensive tackle
- Years playing in the NFL: 1990-1998
- Cause of death: Car crash
Ken Stabler (1945-2015)
- NFL teams: Oakland Raiders, Minnesota Vikings, Houston Oilers, New Orleans Saints
- Position: Quarterback
- Years playing in the NFL: 1968-1984
- Cause of death: Colon cancer
Kevin Turner (1969-2016)
- NFL teams: New England Patriots, Philadelphia Eagles
- Position: Fullback
- Years playing in the NFL: 1992-1999
- Cause of death: Lou Gehrig’s disease
Mike Webster (1952-2002)
- NFL teams: Pittsburgh Steelers and Kansas City Chiefs
- Position: Center
- Years playing in the NFL: 1974-1990
- Cause of death: Heart attack
Mosi Tatupu (1955-2010)
- NFL teams: New England Patriots, Los Angeles Rams
- Position: Running back
- Years playing in the NFL: 1978-1991
- Cause of death: Heart attack
Ollie Matson (1930-2011)
- NFL teams: Chicago Cardinals, Los Angeles Rams, Detroit Lions, Philadelphia Eagles
- Position: Running back
- Years playing in the NFL: 1952-1966
- Cause of death: Complications of dementia
Paul Oliver (1984-2013)
- NFL teams: San Diego Chargers, New Orleans Saints
- Position: Safety
- Years playing in the NFL: 2007-2011
- Cause of death: Self-inflicted gunshot wound
Phillip Adams (1988-2021)
- NFL teams: San Francisco 49ers, New England Patriots, Seattle Seahawks, Oakland Raiders, New York Jets, Atlanta Falcons
- Position: Cornerback
- Years playing in the NFL: 2010-2015
- Cause of death: Murder-suicide
Ralph Wenzel (1943-2012)
- NFL teams: Pittsburgh Steelers, San Diego Chargers
- Position: Guard
- Years playing in the NFL: 1966-1973
- Cause of death: Complications of dementia
Ray Easterling (1949-2012)
- NFL teams: Atlanta Falcons
- Position: Safety
- Years playing in the NFL: 1972-1979
- Cause of death: Self-inflicted gunshot wound
Rob Lytle (1954-2010)
- NFL teams: Denver Broncos
- Position: Running back
- Years playing in the NFL: 1977-1983
- Cause of death: Heart attack
Shane Dronett (1971-2009)
- NFL teams: Denver Broncos, Detroit Lions, Atlanta Falcons
- Position: Defensive lineman
- Years playing in the NFL: 1992-2002
- Cause of death: Self-inflicted gunshot wound
Terry Long (1959-2005)
- NFL teams: Pittsburgh Steelers
- Position: Guard
- Years playing in the NFL: 1984-1991
- Cause of death: Suicide by drinking a gallon of antifreeze
Tom McHale (1963-2008)
- NFL teams: Tampa Bay Buccaneers, Philadelphia Eagles, Miami Dolphins
- Position: Offensive guard
- Years playing in the NFL: 1987-1995
- Cause of death: Drug overdose
Tommy Nobis (1943-2017)
- NFL teams: Atlanta Falcons
- Position: Linebacker
- Years playing in the NFL: 1966-1976
- Cause of death: Unspecified extended illness
Tyler Sash (1988-2015)
- NFL teams: New York Giants
- Position: Safety
- Years playing in the NFL: 2011-2012
- Cause of death: Accidental overdose of painkillers
Vincent Jackson (1983-2021)
- NFL teams: San Diego Chargers, Tampa Bay Buccaneers
- Position: Wide receiver
- Years playing in the NFL: 2005-2016
- Cause of death: Chronic alcohol use