Former NFL receiver Demaryius Thomas diagnosed with stage 2 CTE

Contact: Julia Manning | 515-201-7199 |

(Boston) – The family of Demaryius Thomas is announcing today that Boston University CTE Center researchers diagnosed the former NFL wide receiver with stage 2 (of 4) chronic traumatic encephalopathy (CTE). Thomas died in December 2021 at the age of 33. His family is releasing the findings of his brain study through the Concussion Legacy Foundation (CLF), which arranged the brain donation, to help raise awareness of CTE and encourage the football community to support research.    

“Once I became aware of CTE and began to familiarize myself with the symptoms, I noticed that Demaryius was isolating himself and I saw other changes in him,” said Katina Smith, Demaryius’ mother. “He was just so young, and it was horrible to see him struggle. His father and I hope all families learn the risks of playing football. We don’t want other parents to have to lose their children like we did.”

Stage 2 CTE is associated with progressive behavior, cognitive and mood abnormalities. In the years before he died, Thomas developed depression, anxiety, panic attacks, and trouble with his memory. Stage 4 is the most severe stage of CTE and is usually associated with dementia.

"Like so many that have gone before, we found stage 2 CTE in the brain of Demaryius Thomas. The question I keep asking myself is 'When will enough be enough?' When will athletes, parents and the public at large stop ignoring the risks of American football and insist that the game be changed to reduce subconcussive hits and that the athletes be comprehensively evaluated at the beginning and end of every season?” said Dr. Ann McKee, chief of neuropathology for the VA Boston Healthcare System and director of the BU CTE Center and VA-BU-CLF/UNITE Brain Bank.

Concussion Legacy Foundation CEO and co-founder Dr. Chris Nowinski reached out to the Thomas family to propose the CTE study. Bobby Thomas, Demaryius’ father, alongside Katina Smith graciously agreed to make the donation to learn more about why their son changed, and to help others.

“The football community would have no idea why so many former players struggle with neurological disorders after their career without the families who say yes to brain donation, so I want to thank Bobby Thomas and Katina Smith - and all families - for their trust in Dr. McKee and this team,” said Dr. Nowinski, a former football player at Harvard University. “I hope this is a wake-up call to high profile current and former NFL players that CTE is rampant among them, and they need to get involved in creating real solutions. CTE should be their number one off-the-field issue.”

Thomas played 10 seasons in the NFL for the Denver Broncos, New York Jets, and Houston Texans, making four Pro Bowl rosters, and winning Super Bowl 50 with the Denver Broncos. Thomas was the 22nd pick in the first round of the 2010 draft out of Georgia Tech, and in all played 16 years of tackle football before announcing his retirement at age 33 in 2021, six months before his death. His cause of death has not yet been reported.

There has been speculation his death may be related to an epileptic seizure. Although late-stage CTE can be associated with epilepsy, it is far more likely that he developed post-traumatic epilepsy after a motor vehicle accident and fall he experienced several years before his death.

Thomas is one of more than 300 former NFL players who have been diagnosed with CTE by Dr. McKee and the BU CTE Center research team.

Former and current NFL players and their families worried about possible CTE symptoms can reach out to the Concussion Legacy Foundation HelpLine for support at The HelpLine staff provides personalized resources and recommendations for treatment.


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