Chronic traumatic encephalopathy (CTE) has been identified in postmortem studies of the brains of former professional American football and hockey players and reported in high-impact medical journals. In these articles and a recent summary, authors suggested CTE resulted from years of repetitive head impacts and, with conviction, concluded traumatic brain injury (TBI) causes CTE.1 These conclusions have been widely publicised, as have adamant commentaries and media placements by the articles’ authors and others,2 creating a public perception that contact sport participation indeed causes CTE.3
Risks of CTE as a ‘diagnosis’
Other investigators have called for tempering conclusions, warning that former athletes experiencing symptoms including headaches may, upon hearing these publicised results, believe that they are developing CTE. There is a risk that these athletes may fail to acknowledge other possible mental health causes for their conditions, lose hope and decline into self-destructive behaviour, when appropriate treatment might well manage their symptoms.4 5 Tragically, the fatal shootings in Manhattan at the time of this writing were committed by a former high school football athlete who suspected he had CTE and, according to a suicide note, blamed the National Football League (NFL) for concealing the dangers of playing football and was seeking revenge.6 However, all CTE studies to date used either case series or cross-sectional analyses.7 These are not strong study designs from an epidemiological standpoint and are helpful for hypothesis generation but not hypothesis testing or determining causation. This editorial aims to describe how a population-based case-control study of …
