Chronic traumatic encephalopathy, suicides and parasuicides in professional American athletes: the role of the forensic pathologist.

We present 5 cases of professional American contact sport athletes who committed parasuicides and suicides aged 50, 45, 44, 36, and 40 years old. Full forensic autopsies and immunohistochemical analyses of the brains revealed chronic traumatic encephalopathy (CTE). The brains appeared grossly normal at autopsy without gross evidence of remote traumatic injuries or neurodegenerative disease. Brain immunohistochemical analyses revealed widespread cerebral taupathy in the form of neurofibrillary tangles and neuritic threads without neuritic amyloid plaques. CTE refers to chronic cognitive and neuropsychiatric symptoms of chronic neurodegeneration following a single episode of severe traumatic brain injury or repeated episodes of mild traumatic brain injury. CTE can only be definitively diagnosed by direct tissue examination. Without full autopsies and immunohistochemical brain analyses these cases would never have been identified. Forensic pathologists will play a vital and central role in the emerging disease surveillance of CTE in professional American athletes, in the identification of CTE cases, and in the establishment of the epidemiology of CTE, with the goal of eventually developing preventive and interventional therapeutic protocols for CTE outcomes.