Study Shows One in Four Former NFL Players May Develop CTE

A recent study conducted by researchers in Massachusetts indicates that one in four former NFL athletes could suffer from chronic traumatic encephalopathy (CTE), a debilitating brain disease discovered only posthumously. The study, published in The BMJ, analyzed the deaths of NFL players between 2008 and 2021.

Out of over 1,700 deceased players, 338 had their brains examined. Findings revealed that 315 of these players were diagnosed with CTE. Over the last six years, as brain donation for research became more prevalent, 235 players donated their brains, with more than 210 confirmed to have CTE.

CTE is known to affect brain functionality. The Centers for Disease Control and Prevention (CDC) suggest that CTE results from abnormal protein accumulation that damages brain tissue and initiates cell death. The disease often appears in individuals who have a history of repeated head impacts, particularly among football players. Nevertheless, boxers, soccer and hockey players, military personnel, and first responders have also been linked with CTE.

Symptoms of CTE can take years to surface and persist for extended periods. While specific symptoms remain uncertain, those diagnosed with CTE exhibit difficulties in thinking, emotional instability, mood changes, and serious suicidal thoughts or behaviors, according to the CDC. Yet, these symptoms do not confirm a CTE diagnosis. Professional consultation is encouraged as treatments exist to alleviate many of these symptoms.

Efforts to comprehend CTE better, including its origins, associated risk factors, and earlier diagnostic methods, are ongoing, as stated by Boston University. The study found numerous NFL players received a CTE diagnosis postmortem. A 2023 report mentioned that of 376 former NFL players reviewed by Boston University’s CTE Center, 345 were diagnosed with the disease.

Individuals Recently Diagnosed with CTE

Former Dallas Cowboys defensive end Marshawn Kneeland was diagnosed with Stage 1 CTE posthumously after his suicide in a high-speed police chase. Aaron Hernandez, whose suicide in 2017 was linked to severe CTE, was found to have Stage 3 CTE while incarcerated for murder.

Frank Wycheck of the Tennessee Titans faced a fatal head injury at home in 2023. He had Stage 3 CTE. Demaryius Thomas, another NFL Pro Bowl player, manifested depression, anxiety, and CTE symptoms before his 2021 death confirmed his Stage 2 CTE diagnosis. Irv Cross, a former player turned CBS anchor, faced significant mental health declines and showed Stage 4 CTE postmortem.

Phillip Adams, an NFL veteran, fatally attacked six individuals in South Carolina before taking his life in 2021. His autopsy revealed Stage 2 CTE. Shane Tamura, guilty of four murders in New York City, had CTE and claimed grievances against the league, despite never playing for the NFL.

Research continues to focus on understanding and mitigating CTE within sports and other at-risk careers. Copyright 2026 Nexstar Media Inc. All rights reserved.