Demaryius Thomas Diagnosed With Stage 2 CTE in Posthumous Brain Examination

The former All-Pro wide receiver also dealt with unrelated seizures before his death last December at age 33.

Boston University researchers revealed Tuesday former All-Pro wide receiver Demaryius Thomas had the degenerative brain disease known as chronic traumatic encephalopathy (CTE) late in his life, according to The New York Times.

Thomas was found dead in his home in Roswell, Ga., on Dec. 9, 2021, at age 33. At the time, the receiver’s family believed his death was related to seizures that Thomas had faced since a ’19 car crash. Boston University researchers still believe that he most likely died after a seizure, but the coroner’s office in Fulton County, Ga., has not yet ruled on the cause of his death.

“[Thomas] had two different conditions in parallel,” Dr. Ann McKee, the neuropathologist who studied Thomas’s brain, said.

She added that seizures were not generally associated with CTE. 

“CTE itself does not cause death. You don’t die from CTE,” McKee told ABC News. “What CTE does is it changes your behavior and your personality.”

Family members said that in addition to the seizures that began in 2020, Thomas dealt with conditions commonly associated with Stage 2 CTE: memory loss, paranoia and other erratic behavior, especially in the year leading up to his untimely death.

“His mood would change, and he would also isolate himself sometimes,” Thomas’s mother, Katina Stuckey Smith, told ABC News. “He was, like, ‘Mom, I don’t know what’s going on with my body. You know, I gotta get myself together,’ and he said, ‘I don’t feel like myself anymore.’”

Thomas was born in Montrose, Ga., and played for Georgia Tech. He stayed at the ACC program through his junior year, tallying 46 receptions for 1,154 receiving yards and eight receiving touchdowns that season. He went on to be selected in the first round of the 2010 NFL draft, taken at No. 22 by the Broncos.

Thomas spent eight seasons in Denver, reaching the Pro Bowl for three consecutive campaigns from 2012 to ’14. He won the Super Bowl alongside Peyton Manning in ’15, but arguably his most memorable moment came three seasons before, when Thomas took a slant from Tim Tebow 80 yards to the house in overtime to beat the Steelers in the divisional round of the playoffs.

During his 10-season career with the Broncos, Texans, Patriots and Jets, Thomas caught 724 passes, tallying 9,763 yards and 63 touchdowns. He officially retired in June 2021, ending his professional football career where it all began.