Waters, of course, became one of the tragic examples of that damage after he took his own life in 2006. Waters' family donated his brain to Boston researchers studying chronic traumatic encephalopathy in former football players. CTE, normally found in much older people, can cause dementia, memory loss, and depression.
The May 2 death of retired linebacker Junior Seau raised the issue again in a dramatic way. At a time when more than 2,000 former players are involved in lawsuits against the NFL seeking damages for its handling of their concussions, the suicide of a 43-year-old, Hall of Fame-bound star is stop-the-presses news.
There is another issue here, though, and it has been overlooked in much of the discussion.
Steroids. Could anabolic steroids and other performance- enhancing drugs, including stimulants, play a role in all this?
Like former Chicago Bears safety Dave Duerson, Seau shot himself in the chest. Duerson did so specifically because he wanted his brain to be intact for study. The researchers in Boston found severe CTE damage. It isn't clear that Seau had the same intention, but it isn't much of a leap to think so.
There is no evidence Seau used PEDs. This isn't about accusing him or anyone else. But the stakes are too high here to pretend PEDs aren't in the mix when talking about professional football players of the last three decades. Guskiewicz did a confidential survey of retired players two years ago in which about 10 percent admitted using steroids during their careers.
"We haven't been able to look at it closely," Guskiewicz said in a phone conversation Friday. "It is now something we ask players who come through the Center [for the Study of Retired Athletes at UNC]. We think it's important to know."
Players may be quicker to reveal information about concussions, which are part of the game, than about using PEDs, which could cast a cloud over their achievements. And with the lawsuits, there is a financial incentive to blame concussions for post-career problems. There is nothing to gain from acknowledging self-inflicted damage.
Guskiewicz's study found links to PED use and later musculoskeletal injuries. It also cited higher incidence of depression, attention deficit disorder, and alcohol abuse among those who admitted PED use.
A number of studies have linked steroid use to depression and impulsive behavior. That can be a formula for suicide.
"The question has been raised numerous times about the effect of PEDs," Guskiewicz said. "We just don't have the studies to tease out that information. We do know some of the former players found to have CTE were steroid users. Some, we have no idea. We know damage is caused by concussion and subconcussive impact, but the effect in combination with PEDs, we just don't know."
It is not an either/or thing. It is possible for a player to have issues because of CTE that are exacerbated by PED-related depression.
Again, the point is not to play Gotcha with former players. The point is to identify all the factors causing this crisis in hopes of making football and other sports not just safer, but sustainable. Guskiewicz has gone from an outspoken critic of the NFL's concussion policies to a member of the league's committee on head, neck, and spine injuries.
"There is a feeling, and I share it, that we need to slow down a little," Guskiewicz said. "We may have been too quick to say it is football causing all of this. There's a danger that former players could feel depressed or down, decide, 'I must have that [CTE],' and decide to just turn it in."
Guskiewicz's committee was behind the decision to change kickoff rules last season, a move he said reduced concussions on kickoffs by 42 percent.
"The game has to change, I think," Guskiewicz said. "That's why I agreed to be on the committee. I think [NFL commissioner] Roger Goodell is serious about this. I think this will be his legacy - player safety."
If the lawsuits continue piling up, pro football could go the way of bear-baiting on Goodell's watch. The lawsuits are the result of decades of ignorance, some of it willful, about the seriousness of concussions.
If the game is to survive, it is going to take science, research, and frank discussion. That will have to include knowing what role PEDs play in the whole complicated nightmare.
Contact Phil Sheridan at 215-854-2844, firstname.lastname@example.org, or on Twitter @Sheridanscribe. Read his blog, "Philabuster,"
Read his columns at philly.com/philsheridan