Former Cowboy Kneeland had stage 1 CTE when he died by suicide, foundation finds

Researchers at the Boston University CTE Center diagnosed the former Dallas Cowboys defensive end with chronic traumatic encephalopathy, a disease likely caused by repeated head injuries.

Former Dallas Cowboys defensive end Marshawn Kneeland had stage 1 CTE when he died by suicide in November, according to an announcement from the Concussion and CTE Foundation on Tuesday.

“Unfortunately, I was not surprised to find CTE in the brain of Mr. Kneeland, because we have found this progressive brain disease in nearly half of the athletes we’ve studied who have died before the age of 30,” Dr. Ann McKee, director of the Boston University CTE Center and chief of neuropathology for the VA Boston Healthcare System, said in the announcement.

CTE — or chronic traumatic encephalopathy—is a disease likely caused by repeated head injuries, according to the Mayo Clinic. Stage 1 CTE has been linked to headaches, loss of attention and concentration, as well as short-term memory problems, depression, "explosivity and executive function issues," in some individuals, according to the CTE Society.

A 2023 study of about 150 athletes who played contact sports such as football, hockey and rugby and died before age 30 found more than 40% had early-stage CTE.

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