Boston University researchers released a study of the brains of 202 deceased football players. The brains were donated by relatives of the players; the relatives were concerned about the behavior of the players. The players were active in various levels of football: pre-high school (2), high school (14), college (53), semi-pro (14), Canadian league (8) and NFL (111). 86.6% (177) had chronic traumatic encephalopathy (CTE), which is a degenerative brain disease that can result in troubling behavior, disturbed moods, impaired thinking, agitation, impulsivity, explosive tempers and memory loss. More than half of the players contemplated suicide. Suicide, in fact, was the leading cause of death among those with mild CTE.
The participants played football for an average of 15 years. More than 90 percent of college players in the study sample had CTE. Among the 111 National Football League players whose brains were donated, CTE was found in all but one.