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Former NFL defensive end Marshawn Kneeland was posthumously diagnosed with Stage 1 chronic traumatic encephalopathy (CTE), Boston University’s CTE Center announced after his family donated his brain for research following his death in November 2025.
Kneeland died by suicide at the age of 24. Researchers determined he had Stage 1 CTE, the earliest of the disease’s four stages. CTE is a progressive brain disease associated with repeated head impacts and can only be diagnosed after death.
In a statement released Tuesday, Kneeland’s family said the diagnosis provides greater understanding of the challenges he may have experienced while emphasizing that it does not change the tragedy of his passing.
“While this diagnosis does not change the tragedy of his passing, it provides important context about some of the struggles he may have been facing,” the family said. “We share this information to help people understand what NFL and other high-contact sport athletes might be struggling with. Raising awareness is important to us. We continue to remember Marshawn with compassion for the person he was, rather than defining him by the final moments of his life.”
The Boston University CTE Center stressed that suicide is “complex and multifactorial” and cautioned that people should not view a postmortem CTE diagnosis as the cause of a person’s death by suicide.
Mental Health Concerns Predated NFL Career
According to records obtained by ESPN, concerns about Kneeland’s mental health dated back to his time at Western Michigan University in 2020.
In one incident, police required him to surrender a firearm until he received clearance from a counselor. In another, authorities responded after a friend reported concerns for his well-being. Officers located Charlie Kneeland on railroad tracks, where he reportedly said he hoped a train would strike him. Medical personnel transported him to a hospital following the incident.
Kneeland died after a high-speed pursuit with Texas authorities in November 2025. According to the Texas Department of Public Safety, a trooper attempted to stop his vehicle for speeding after it reportedly reached speeds exceeding 145 mph while making multiple unsafe lane changes. Officers later learned he had expressed suicidal thoughts before locating his crashed vehicle. Kneeland fled on foot, and officers later found him dead.
Researchers Continue Studying Early-Stage CTE
Dr. Ann McKee, director of Boston University’s CTE Center and chief of neuropathology for the VA Boston Healthcare System, said the diagnosis reflects findings seen in many young athletes studied by the center.
“We have found this progressive brain disease in nearly half of the athletes we’ve studied who have died before the age of 30,” McKee said. “Thanks to the generosity of our brain donor families, we now better understand the earliest stages of CTE, and it is bringing us closer than ever to diagnosing it during life.”
