CTE and the NFL: Players Whose Deaths Have Been Linked to the Disease
The family of former Dallas Cowboys defensive end Marshawn Kneeland has revealed that the 24-year-old was suffering from early-stage chronic traumatic encephalopathy (CTE) at the time of his death, adding his name to a growing list of athletes found to have the degenerative brain disease.
Researchers at Boston University’s CTE Center diagnosed Kneeland with Stage 1 CTE following an examination of his brain after he died by suicide in November 2025.
Kneeland shot himself after evading authorities in his vehicle and fleeing a car crash on foot.
The chase happened after police said Kneeland didn't stop for Texas Department of Public Safety troopers over a traffic violation. Authorities lost sight of the vehicle before locating it crashed minutes later.
As authorities were looking for Kneeland after he fled the crash site on foot, a dispatcher told officers that people who knew him had received a group text from Kneeland "saying goodbye," indicating he might be suicidal.
His family said they chose to make the findings public to help raise awareness of the challenges that athletes in contact sports may face.
The condition has been identified in former contact-sport athletes and military veterans, but it can currently only be definitively diagnosed after death. It is known to cause violent mood swings, impulsive behavior and depression.
A 2023 study from Boston University, funded by the National Institutes of Health, found evidence of CTE in more than 40 percent of a group of contact-sport athletes who died before the age of 30, suggesting a significant prevalence of the condition among athletes who pass away despite being young.
As awareness has grown, sports organizations have introduced concussion protocols, though researchers say more work needs to be done to reduce the number and strength of head impacts in contact sports, particularly in young athletes.
What Is CTE?
Chronic traumatic encephalopathy, commonly known as CTE, is a progressive neurodegenerative disease caused by repeated head impacts over time.
It is characterized by the abnormal buildup of a protein called tau in the brain, which gradually damages brain tissue and interferes with normal brain function. It causes similar damage to the brain as seen in those with Alzheimer’s disease.
CTE has most commonly been identified in athletes who participate in contact sports such as football, boxing, soccer, rugby and hockey, as well as in some military veterans.
Unlike a concussion, which is a single traumatic brain injury, CTE is believed to develop from the cumulative effect of repetitive head impacts, including many that may not cause obvious symptoms at the time they occur.
A major challenge for doctors and scientists is that CTE can currently only be confirmed through post-mortem examination of brain tissue, limiting the ability to identify and study the disease in living patients.
What Are The Stages And Symptoms Of CTE?
The condition is generally classified in four stages, with symptoms and brain damage becoming more severe as the disease progresses.
Stage 1 CTE, the earliest form, which was diagnosed in Kneeland’s case, is often associated with headaches and difficulty concentrating, while those with Stage 2 may present with depression and explosive episodes. Those with Stages 3 and 4 are believed to present with more varied cognitive difficulties.
Symptoms can range from cognitive impairment like trouble thinking, memory loss, and problems planning or organizing, to behavioral changes like aggression or impulse behavior. Some may also experience mood changes like depression, emotional instability, substance misuse or suicidal thoughts and behavior. It can also result in difficulty walking or with balance, shaking, trouble with speech, and also the gradual loss of movement.
Scientists say that symptoms vary significantly between individuals and note that while early death has occurred among some individuals later found to have CTE, the disease itself should not automatically be viewed as the cause of a person’s death, which can be caused by multiple factors.
Is There A Cure For CTE?
There is currently no cure for CTE and no treatment capable of reversing the underlying brain damage once it has occurred. Medical care instead focuses on managing symptoms, including depression, anxiety and mood disorders.
Researchers are working to develop biomarkers and imaging techniques that could allow doctors to diagnose CTE during life, a breakthrough that many experts believe is critical to developing future therapies.
In the meantime, prevention remains crucial. Experts have called for reductions both in the number and intensity of head impacts in sports through rule changes, improved coaching practices, safer training methods and continued efforts to limit exposure to repetitive brain trauma at all levels of competition.
List of NFL Players With CTE-Related Deaths
- Marshawn Kneeland
- Ray Abruzzese
- Phillip Adams
- Kenneth Adamson
- George Andrie
- Mark Arneson
- Rick Arrington
- Chuck Arrobio
- George Atkinson
- George Atkinson III
- Maxie Baughan
- Terry Beasley
- Dave Behrman
- Jovan Belcher
- Al Bemiller
- Wes Bender
- Jeff Blackshear
- Forrest Blue
- Dorian Boose
- Daniel Brabham
- Colt Brennan
- Curtis Brown
- Nick Buoniconti
- Lew Carpenter
- Howard Carson
- Howard “Hopalong” Cassady
- Ronnie Caveness
- Henry Childs
- Greg Clark
- Daniel Colchico
- Paul Crane
- Lou Creekmur
- Bobby Crespino
- Chuck Crist
- Irv Cross
- Doug Cunningham
- Art DeCarlo
- Willie Daniel
- George Darrah
- Fred Dean
- Tom DeLeone
- Bill Demory
- Taylor Dever
- Conrad Dobler
- David Drachman
- Shane Dronett
- Dave Duerson
- Pete Duranko
- Ray Easterling
- Chris Eitzmann
- Kevin Ellison
- James Evans
- Mel Farr
- Grant Feasel
- Gene Felker
- Cullen Finnerty
- Danny Fulton
- Frank Gifford
- Daren Gilbert
- Cookie Gilchrist
- Nesby Glasgow
- John Grimsley
- Jason Hairston
- Darryl Hammond
- Carlton Haselrig
- Rip Hawkins
- Steve Heimkreiter
- Chris Henry
- Aaron Hernandez
- Wally Hilgenberg
- John Hilton
- Glen Ray Hines
- Nate Hobgood-Chittick
- Paul Hornung
- Jim Houston
- Jim Hudson
- Claude Humphrey
- Gerry Huth
- Vincent Jackson
- Lionel James
- Darrius Johnson
- John Henry Johnson
- Ron Johnson Sr.
- Vaughan Johnson
- Terry Joyce
- Tom Keating
- Bob Kuechenberg
- Jim Kiick
- Frank LeMaster
- Bill Lenkaitis
- Greg Lens
- Terry Long
- Edward Lothamer
- Jim Lynch
- Rob Lytle
- Charles Mackey
- John Mackey
- Greg Marx
- Ollie Matson
- Tommy McDonald
- Keli McGregor
- Tom McHale
- Kenny McKinley
- Steve McMichael
- Fred McNeill
- Earl Morrall
- Larry Morris
- Guy Morriss
- Tommy Nobis
- Joe O’Malley
- Paul Oliver
- Chuck Osborne
- Don Paul
- Ray Perkins
- Joe Perry
- Richard Pickens
- Cyril Pinder
- Mike Pitts
- Mike Pyle
- Bob Riley
- Isiah Robertson
- Adrian Robinson
- Rocky Rosema
- Scott Ross
- Max Runager
- Tyler Sash
- Eric Scoggins
- Clyde Scott
- Jake Scott
- Junior Seau
- Bubba Smith
- Joey Smith Sr.
- Steve Smith
- Robert Sowell
- Ken Stabler
- Jeff Staggs
- Bill Stanfill
- Justin Strzelczyk
- Jerry Sturm
- Pat Sullivan
- Mosi Tatupu
- Daniel Te’o-Nesheim
- Demaryius Thomas
- Bill Troup
- Max Tuerk
- Kevin Turner
- Tommy Vaughn
- Frank Wainright
- Fulton Walker
- Andre Waters
- Cornell Webster
- Mike Webster
- Jim Welch
- Ralph Wenzel
- Charles White
- Jesse Whittenton
- John Wilbur
- Ben Williams
- Stanley Wilson Jr.
- Jeff Winans
- Dennis Wirgowski
- Willie Wood
- Frank Wycheck
- Roger Zatkoff
If you or someone you know is considering suicide, contact the 988 Suicide and Crisis Lifeline by dialing 988, text “988” to the Crisis Text Line at 741741 or go to 988lifeline.org
Contact Newsweek editors on this story: James Rushton and Tony Phillips
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This story was originally published July 8, 2026 at 8:45 AM.