The death of the sportsman, who was found unconscious in his Oceanside, California home on 2 May (12), with a gunshot wound to the chest, was officially ruled a suicide.
Autopsy and toxicology results showed no signs of drugs or alcohol in his system, and an initial examination of Seau's brain showed no apparent damage, but researchers at the National Institutes of Health have now released their findings after thoroughy examining the tissue to determine whether Seau suffered any longterm affects from his years on the football field.
The results have now been published and scientists discovered that Seau had been battling chronic traumatic encephalopathy (CTE), a degenerative disease typically caused by multiple hits to the head.
Lead researcher Dr. Russell Lonser tells ABC News patients struggling with the condition typically display symptoms ""such as impulsivity, forgetfulness, depression (and) sometimes suicidal ideation"".
The former San Diego Chargers icon, 43, did not leave a suicide note. He played in the NFL for 20 years.