Marshawn Kneeland, a 24-year-old defensive end for the Dallas Cowboys, died by suicide last November, leaving family, friends, and fans searching for answers. A promising athlete who had recently scored his first NFL touchdown, Kneeland’s sudden death shocked the football community. This week, his family revealed that a post-mortem examination diagnosed him with early-stage chronic traumatic encephalopathy (CTE), a neurodegenerative disease linked to repeated head trauma and commonly found in football players.

CTE is caused by the buildup of abnormal tau protein in the brain, similar to that seen in Alzheimer's disease. It is associated with a range of symptoms, including cognitive decline, mood disturbances, impulsive behavior, and motor dysfunction. The condition can only be definitively diagnosed after death, and much about its progression remains unclear.

The diagnosis of CTE in Kneeland’s brain adds to growing evidence connecting the disease to high-impact contact sports. Research has shown a high prevalence of CTE among former football players at all levels. A 2017 study examining the brains of 111 deceased NFL athletes found that all but one showed signs of the disease. Additionally, CTE has been identified in younger athletes, including a former high school player who, after killing four people and himself in a 2022 incident, requested his brain be tested for the disease; the autopsy confirmed CTE despite the absence of a professional football career.

In response to mounting scientific findings and public concern, the NFL has increased its investment in CTE research and has implemented measures aimed at reducing head injuries. These include new rules limiting high-risk plays and comprehensive concussion protocols to safeguard players before they return to the field. The league has committed $100 million to study neurodegenerative effects linked to football-related head trauma.

Despite these efforts, football remains a sport with substantial risk of brain injury. Experts urge caution, particularly regarding youth participation. Medical professionals recommend delaying exposure to tackle football and other contact sports that involve frequent head impacts until at least high school age. Kneeland began playing tackle football at age seven, highlighting concerns about early exposure.

While much about CTE is still unknown, the diagnosis in Kneeland’s case underscores the need for continued research and preventive strategies to protect athletes at all levels. Coaches, parents, and sports organizations face mounting pressure to prioritize safety and increase awareness of the potential long-term consequences of repeated head trauma in high-impact sports.