The brain disease has most commonly been found in athletes in contact sports and others with a history of repeated brain trauma.

Shane Devon Tamura — the man who killed at least four people in a New York City office building — claimed in a suicide noted that he suffered from chronic traumatic encephalopathy (CTE) while slamming the NFL. “Study my brain please,” Tamura, a former high-school football player, wrote in the note. "I'm sorry."