New research indicates that as many as one in four former National Football League players may develop chronic traumatic encephalopathy (CTE) over their lifetimes. The study, published in The BMJ and covering a six-year period from 2016 to 2021, examined the brains of 878 deceased former NFL players. Of those examined, at least 215 individuals, or 24.5%, showed signs of CTE. The study notes that the actual prevalence could be higher, as 643 brains were not analyzed.
If these findings were applied to the current NFL, which has 1,696 active roster players across 32 teams, it suggests that approximately 415 players could be diagnosed with CTE. The neurodegenerative disease, linked to repeated head trauma and blows to the head, can only be definitively diagnosed after death through brain examination. Symptoms include memory loss, mood swings, and erratic behavior.
Dr. Julian Bailes, a neurosurgeon and chief medical advisor for Q-30 Sports Science, who has studied CTE for decades, stated that the study's results "should be a call to action for everyone involved in football." He emphasized the importance of addressing repetitive head impacts, not just diagnosed concussions, and called for "proactive brain protection" at all levels of the sport. He advocated for advancements in rules, training, and equipment to reduce the forces experienced by the brain.
The NFL acknowledged the findings, stating, "The NFL remains committed to ensuring that the NFL community has access to robust — and expanding — set of resources to enhance their physical and mental well being." The league also noted its continuous efforts to make the game safer by implementing strategies to reduce concussions and head impacts.
The NFL Players Association responded to the study, calling the findings "a call to action across the entire football ecosystem." In the 2025 NFL season, 168 in-game concussions were documented, a 30% increase from the 129 recorded in the 2024 season. These figures also included 538 evaluations and 26 medical timeouts.