Special Report

Famous Football Players Known to Have Had CTE

Kent Horner / Getty Images Sport via Getty Images

The football world was shocked when retired former Denver Broncos wide receiver Demaryius Thomas died last year at age 33 after suffering a seizure, initially thought to be related to injuries from a 2019 auto accident. Now doctors know more about a key factor contributing to his death: In July, Thomas became the latest NFL player to be diagnosed posthumously with CTE. 

CTE – chronic traumatic encephalopathy – is a degenerative brain disease that has been linked to recurring hits to the head and episodes of concussion, which are common in football and other contact sports.

A major challenge dealing with CTE is it can only be diagnosed postmortem, meaning it is left untreated and can lead to player’s death at a young age. One study found that the brains of 110 out of 111 former NFL players showed signs of CTE when autopsied.

To compile a list of 35 professional football players whose deaths are at least partially attributable to CTE, 24/7 Tempo reviewed profiles of players published by the Concussion Legacy Foundation and articles published by Boston University’s CTE Center. We also reviewed archived news stories about deceased football players published on ESPN, CNN, Sports Illustrated, NPR, and other online sources.

Click here to see a list of famous football players known to have had CTE

Some of the most common symptoms of CTE are confusion, impaired judgment, and severe mood swings that often include aggressive responses. Several of the former football players on the list have had a history of violent behavior. (These are 33 athletes with famously bad tempers.)

In some cases, the violence goes to the extreme. For instance, in 2015, New England Patriots tight end Aaron Hernandez was found guilty of the 2012 murder of semi-pro linebacker Odin Lloyd and later died in prison, an apparent suicide; and last year, cornerback Phillip Adams, who’d played for numerous NFL teams, shot six people before turning the gun on himself.

In recent years, suicide has been widely cited as being associated with CTE. Of the 35 men on the list, at least 12 have died by their own hand. (These are 37 violent celebrity deaths.)

Source: Jared Wickerham / Getty Images

Aaron Hernandez (1989-2017)
> Position: Tight end
> Years playing in the NFL: 2010-2012
> NFL teams: New England Patriots
> Cause of death: Suicide by hanging

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Source: Doug Pensinger / Getty Images Sport via Getty Images

Adrian Robinson (1989-2015)
> Position: Linebacker
> Years playing in the NFL: 2012-2015
> NFL teams: Pittsburgh Steelers, Philadelphia Eagles, Denver Broncos, San Diego Chargers, Washington Redskins
> Cause of death: Suicide by hanging

Source: Gene Sweeney / Getty Images Sport via Getty Images

Andre Waters (1962-2006)
> Position: Defensive back
> Years playing in the NFL: 1984-1995
> NFL teams: Philadelphia Eagles, Arizona Cardinals
> Cause of death: Self-inflicted gunshot wound

Source: Michael Ochs Archives / Michael Ochs Archives via Getty Images

Bubba Smith (1945-2011)
> Position: Defensive lineman
> Years playing in the NFL: 1967-1976
> NFL teams: Baltimore Colts, Oakland Raiders, Houston Oilers
> Cause of death: Drug overdose

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Source: Mike Zarrilli / Getty Images Sport via Getty Images

Chris Henry (1983-2009)
> Position: Wide receiver
> Years playing in the NFL: 2005-2009
> NFL teams: Cincinnati Bengals
> Cause of death: Car accident

Source: Getty Images / Getty Images Sport via Getty Images

Colt Brennan (1983-2021)
> Position: Quarterback
> Years playing in the NFL: 2008-2010
> NFL teams: Washington Redskins, Oakland Raiders
> Cause of death: Drug overdose

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Cookie Gilchrist (1935-2011)
> Position: Fullback
> Years playing in the NFL: 1962-1967
> NFL teams: Buffalo Bills, Denver Broncos, Miami Dolphins
> Cause of death: Bladder cancer

Daniel Te’o-Nesheim (1987-2017)
> Position: Linebacker
> Years playing in the NFL: 2010-2013
> NFL teams: Philadelphia Eagles, Tampa Bay Buccaneers
> Cause of death: Lethal mixture of pills and alcohol

Source: George Rose / Getty Images Sport via Getty Images

Dave Duerson (1960-2011)
> Position: Safety
> Years playing in the NFL: 1983-1993
> NFL teams: Chicago Bears, New York Giants, Phoenix Cardinals
> Cause of death: Self-inflicted gunshot wound

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Demaryius Thomas (1987-2021)
> Position: Wide receiver
> Years playing in the NFL: 2010-2019
> NFL teams: Denver Broncos, Houston Texans, New England Patriots, New York Jets
> Cause of death: Seizure

Source: Public Domain / Wikimedia Commons

Earl Morrall (1934-2014)
> Position: Quarterback
> Years playing in the NFL: 1956-1976
> NFL teams: San Francisco 49ers, Pittsburgh Steelers, Detroit Lions, New York Giants, Baltimore Colts, Miami Dolphins
> Cause of death: Complications from Parkinson’s disease

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Source: Hulton Archive / Archive Photos via Getty Images

Frank Gifford (1930-2015)
> Position: Running back
> Years playing in the NFL: 1952-1960, 1962-1964
> NFL teams: New York Giants
> Cause of death: Natural causes

Source: JoeChristensen / iStock Unreleased via Getty Images

Fred McNeill (1952-2015)
> Position: Linebacker
> Years playing in the NFL: 1974-1985
> NFL teams: Minnesota Vikings
> Cause of death: Lou Gehrig’s disease

Source: Elsa / Getty Images Sport via Getty Images

Greg Clark (1972-2021)
> Position: Tide end
> Years playing in the NFL: 1997-2001
> NFL teams: San Francisco 49ers
> Cause of death: Self-inflicted gunshot wound

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Source: Rick Stewart / Getty Images Sport via Getty Images

John Grimsley (1962-2008)
> Position: Linebacker
> Years playing in the NFL: 1984-1993
> NFL teams: Houston Oilers, Miami Dolphins
> Cause of death: Accidental gunshot wound

Source: wellesenterprises / iStock Editorial via Getty Images

John Mackey (1941-2011)
> Position: Tight end
> Years playing in the NFL: 1963-1972
> NFL teams: Baltimore Colts, San Diego Chargers
> Cause of death: Dementia

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Source: Jamie Squire / Getty Images Sport via Getty Images

Jovan Belcher (1987-2012)
> Position: Linebacker
> Years playing in the NFL: 2009-2012
> NFL teams: Kansas City Chiefs
> Cause of death: Self-inflicted gunshot wound

Source: Kent Horner / Getty Images Sport via Getty Images

Junior Seau (1969-2012)
> Position: Linebacker
> Years playing in the NFL: 1990-2009
> NFL teams: San Diego Chargers, Miami Dolphins, New England Patriots
> Cause of death: Self-inflicted gunshot wound

Source: Rick Stewart / Getty Images Sport via Getty Images

Justin Strzelczyk (1968-2004)
> Position: Offensive tackle
> Years playing in the NFL: 1990-1998
> NFL teams: Pittsburgh Steelers
> Cause of death: Car crash

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Source: Allsport / Getty Images

Ken Stabler (1945-2015)
> Position: Quarterback
> Years playing in the NFL: 1968-1984
> NFL teams: Oakland Raiders, Minnesota Vikings, Houston Oilers, New Orleans Saints
> Cause of death: Colon cancer

Source: Win McNamee / Getty Images News via Getty Images

Kevin Turner (1969-2016)
> Position: Fullback
> Years playing in the NFL: 1992-1999
> NFL teams: New England Patriots, Philadelphia Eagles
> Cause of death: Lou Gehrig’s disease

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Source: Jonathan Daniel / Hulton Archive via Getty Images

Mike Webster (1952-2002)
> Position: Center
> Years playing in the NFL: 1974-1990
> NFL teams: Pittsburgh Steelers and Kansas City Chiefs
> Cause of death: Heart attack

Source: littleny / iStock Editorial via Getty Images

Mosi Tatupu (1955-2010)
> Position: Running back
> Years playing in the NFL: 1978-1991
> NFL teams: New England Patriots, Los Angeles Rams
> Cause of death: Heart attack

Source: Public Domain / Wikimedia Commons

Ollie Matson (1930-2011)
> Position: Running back
> Years playing in the NFL: 1952-1966
> NFL teams: Chicago Cardinals, Los Angeles Rams, Detroit Lions, Philadelphia Eagles
> Cause of death: Complications of dementia

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Source: Handout / Getty Images Sport via Getty Images

Paul Oliver (1984-2013)
> Position: Safety
> Years playing in the NFL: 2007-2011
> NFL teams: San Diego Chargers, New Orleans Saints
> Cause of death: Self-inflicted gunshot wound

Source: Handout / Getty Images Sport via Getty Images

Phillip Adams (1988-2021)
> Position: Cornerback
> Years playing in the NFL: 2010-2015
> NFL teams: San Francisco 49ers, New England Patriots, Seattle Seahawks, Oakland Raiders, New York Jets, Atlanta Falcons
> Cause of death: Murder-suicide

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Source: tupungato / iStock Editorial via Getty Images

Ralph Wenzel (1943-2012)
> Position: Guard
> Years playing in the NFL: 1966-1973
> NFL teams: Pittsburgh Steelers, San Diego Chargers
> Cause of death: Complications of dementia

Ray Easterling (1949-2012)
> Position: Safety
> Years playing in the NFL: 1972-1979
> NFL teams: Atlanta Falcons
> Cause of death: Self-inflicted gunshot wound

Source: Public Domain / Wikimedia Commons

Rob Lytle (1954-2010)
> Position: Running back
> Years playing in the NFL: 1977-1983
> NFL teams: Denver Broncos
> Cause of death: Heart attack

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Source: Tim DeFrisco / Getty Images Sport via Getty Images

Shane Dronett (1971-2009)
> Position: Defensive lineman
> Years playing in the NFL: 1992-2002
> NFL teams: Denver Broncos, Detroit Lions, Atlanta Falcons
> Cause of death: Self-inflicted gunshot wound

Terry Long (1959-2005)
> Position: Guard
> Years playing in the NFL: 1984-1991
> NFL teams: Pittsburgh Steelers
> Cause of death: Suicide by drinking a gallon of antifreeze

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Source: 6381380 / iStock Editorial via Getty Images

Tom McHale (1963-2008)
> Position: Offensive guard
> Years playing in the NFL: 1987-1995
> NFL teams: Tampa Bay Buccaneers, Philadelphia Eagles, Miami Dolphins
> Cause of death: Drug overdose

Source: Scott Cunningham / Getty Images Sport via Getty Images

Tommy Nobis (1943-2017)
> Position: Linebacker
> Years playing in the NFL: 1966-1976
> NFL teams: Atlanta Falcons
> Cause of death: Unspecified extended illness

Source: Handout / Getty Images Sport via Getty Images

Tyler Sash (1988-2015)
> Position: Safety
> Years playing in the NFL: 2011-2012
> NFL teams: New York Giants
> Cause of death: Accidental overdose of painkillers

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Source: Getty Images / Getty Images Sport via Getty Images

Vincent Jackson (1983-2021)
> Position: Wide receiver
> Years playing in the NFL: 2005-2016
> NFL teams: San Diego Chargers, Tampa Bay Buccaneers
> Cause of death: Chronic alcohol use

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