Recently, Junior Seau committed suicide. Sports therapy no longer recognized as just physical, but also mental stability after the fame.

How do sports figures recover completely without affect after so many head injuries?

Pitcher, Mike Flanagan for the Baltimore Orioles committed suicide in 2011.

A chemical imbalance? A mental illness?

Welch football (soccer) player Gary Speed, committed suicide in November 2011.

Jeffrey Lawrence Alm (March 31, 1968 – December 14, 1993) Houston Oilers.

How do these medical professionals base there statistical theory? Do they research prominent sports recorded deaths? Do they then take what may be suspicious in one way or another and chalk it up to mental illness, chemical imbalance, or injury prone categories? Do they compare the population from each amount of years they study, then compare the ratio of mental illness to the ratio of those they consider range? What is the error percentage they use to determine an increase or decrease in mentally ill and mentally sound?

Concussions may play a role in this, but I think its more along the lines of these athletes not being prepared for "after" the game. From the time they are in high school they are put on a pedistal and constantly reminded how great they are, but when they retie they are reminded of how great they were. You add that to failed business deals, marriages and other relationships and it can be disastrous.