mcgraw media

If you’ve watched football long enough, you’ve winced at a hit and wondered what it does to the guy who’s slow to get up. A new study just put a number on part of that question, and it’s a big one.

A Boston University-led study published Wednesday, Oct. 28, in JAMA Network Open estimates that about 75% of former NFL players who died between 2008 and 2023 had chronic traumatic encephalopathy, or CTE. Researchers from Boston University, Mass General Brigham and the Concussion & CTE Foundation worked on the study together.

So, where does 75% come from?

Researchers looked at 2,362 former NFL players who died during that 16-year window. Of the players whose brains were donated for research, around 360 had some degree of CTE. That works out to about 93.5% of the donors studied.

That 93.5% is not the headline number, and here’s why. Families of players who had symptoms are more likely to donate a brain. When the researchers checked death certificates, they found that players with dementia-related cognitive symptoms were five times more likely to be donors. After adjusting for that, they landed on an estimated 74.5% across all 2,362 players.

For comparison, CTE turns up in less than 1% of donors to community brain banks. It’s also a jump from a study published in August, which found that at least 1 in 4 former players who died between 2016 and 2021 had CTE.

Stay with me now, because the wording matters

The study says these players had CTE. It doesn’t say CTE is what killed them. Almost 70% of the players studied died at age 70 or older.

The authors also said the findings don’t predict how many living players, current or former, have CTE. Finding CTE in someone’s brain doesn’t mean they had symptoms. And right now, CTE can only be diagnosed after death, by examining brain tissue. Nobody watching this Sunday can be “diagnosed” with it, so let’s not do that to anyone from the couch.

What about depression?

This is where a lot of fans’ minds go, and for good reason. Two big surveys of former players found a link between head injuries and depression:

• University of North Carolina: 2,552 retired pros were surveyed, and 11.1% reported a past or current clinical depression diagnosis. Players who reported three or more concussions were about three times as likely to report depression as players with none. Players with one or two were about 1.5 times as likely.
• Harvard Football Players Health Study (2019): Nearly 3,500 former players, with an average age of 53, were surveyed. Players with the most concussion symptoms had about six times the risk of depression and anxiety symptoms as players with the fewest. Every five extra seasons played was tied to about 9% higher depression risk.

Mind you, both studies show a link, not proof that concussions cause depression. Both relied on players remembering their own concussions, which almost certainly undercounts them. As Harvard’s Ross Zafonte put it, “not everyone who sustains a concussion is destined for cognitive trouble.”

Depression also has plenty of other causes. A career ends, sometimes overnight. The identity you built since you were 8 years old goes with it. Add chronic pain and ordinary life stress. And in men, depression doesn’t always look like sadness. It often shows up as irritability or anger. That’s worth knowing if the former player is your dad, your husband or your neighbor.

The NFL said it’s committed to making mental and physical health resources available to the NFL community, and it encouraged former players to use them. Those include the NFL Lifeline at 800-453-0078, which offers free, confidential support 24 hours a day, plus The Trust and the Professional Athletes Foundation through the NFLPA. For current players, the league launched a Behavioral Health Network earlier this month.