The revelation of former Dallas Cowboys defensive end Marshawn Kneeland 's chronic traumatic encephalopathy (CTE) diagnosis on July 7 provided a tragic epilogue to the story of his death by suicide in November. But for CTE experts, it did not come as a surprise.
In the press release from the Concussion & CTE Foundation announcing Kneeland's CTE diagnosis, Dr. Ann McKee, the director of Boston University's CTE Center, said his case was part of a larger pattern. According to McKee, CTE diagnoses have been extraordinarily common in young athletes who died young.
"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. McKee said in a statement in the Concussion & CTE Foundation's press release.
MARSHAWN KNEELAND: Cowboys player who died by suicide at 24 diagnosed with CTE
McKee was the primary author on a scientific paper published by the Journal of the American Medical Association examining the prevalence of CTE diagnoses "in young contact sport athletes exposed to repetitive head impacts." In the study, which was published in 2023, McKee et al. studied the brains of 152 athletes who died before the age of 30 for signs of CTE.
Of the 152 brains in the study, 63 of them – 41.4% – showed signs of CTE. Of those 63 diagnosed with CTE, almost all of them – 60 – were mild cases: stages I or II. The remaining three diagnosed in the study had stage III CTE (out of four possible stages). The three brains diagnosed with stage III CTE were from a former NFL player, a former college football player and a former rugby player.
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Kneeland's profile fits with the majority of CTE cases diagnosed in the study. In addition to having a stage I diagnosis of the degenerative brain disease, Kneeland was a Black man who played football and died by suicide.
According to the findings of the study, "Brain donors who had CTE were more likely to be older ... and have a reported Black racial identity. ... Suicide was the most common cause of death." And of 92 brains from football players cited in the article, 48 of them – 52% – showed signs of CTE.
Notably, there were fewer brains from Black athletes in the study than white athletes. Of the 152 studied, 111 were from white athletes, 27 were from Black athletes, 13 were from "missing or other race, including multiracial" athletes and one was from an American Indian or Alaska Native athlete. Of the 27 brains from Black athletes, 16 (59%) showed signs of CTE. There were also more samples from football players (92) than any other sport.
Also worth noting is that suicide was the most common cause of death for all of the 152 people whose brains were included in the study, regardless of CTE diagnosis. Of the 152 brains studied, 87 (57.2%) were from people who died by suicide. Out of those 87, there were 33 brains with signs of CTE (37.9%).
CTE, which stands for chronic traumatic encephalopathy, is a degenerative brain disease that destroys nerve cells in the brain, according to the Mayo Clinic .
It is linked to repeated traumatic brain injury, such as concussions, and has been found in many former boxers, NFL players and military combat veterans after their deaths.
CTE can only be diagnosed after death, with no specific symptoms tied to the disease present while a victim is alive. However, symptoms with possible ties to CTE include memory loss, impulsive behavior and depression.
According to the Mayo Clinic, any symptoms that form as a result of CTE form over several years following multiple instances of traumatic brain injury. They will not necessarily be present immediately after a concussion or other similar injury.
If you or someone you know needs mental health resources and support, please call, text or chat with the 988 Suicide & Crisis Lifeline or visit 988lifeline.org for 24/7 access to free and confidential services.
This article originally appeared on USA TODAY: NFL's Marshawn Kneeland had CTE at 24. Alarming statistic shows that's not rare
