How different are dogfighting and football?

Malcolm Gladwell in The New Yorker:

ScreenHunter_10 Oct. 14 10.09 Mike Webster, the longtime Pittsburgh Steeler and one of the greatest players in N.F.L. history, ended his life a recluse, sleeping on the floor of the Pittsburgh Amtrak station. Another former Pittsburgh Steeler, Terry Long, drifted into chaos and killed himself four years ago by drinking antifreeze. Andre Waters, a former defensive back for the Philadelphia Eagles, sank into depression and pleaded with his girlfriend—“I need help, somebody help me”—before shooting himself in the head. There were men with aching knees and backs and hands, from all those years of playing football. But their real problem was with their heads, the one part of their body that got hit over and over again.

More here. [Thanks to Kris Kotarski.]