This commentary reviews an important cohort study and discusses the possible linkage between contact sport and behavioural dysfunction

In an important cohort study of former professional soccer players from Scotland, Russell et al examined the comparative mental health outcomes of this group.1 Previous work from this group had demonstrated a higher incidence of mortality from neurodegenerative disease. Among professional European-style football players2 the risk factor for neurodegenerative disease in those with contact sport has been demonstrated, in football/soccer, and in American-style football. Several authors have poised behavioural health concerns to be a critical part of the phenotype linked to sport-related neurodegenerative disease such as traumatic encephalopathy syndrome.3 Indeed, concussions and perhaps multiple concussions, have been linked to behavioural health concerns. In this study, Russell et al did not note a higher level of hospitalisations for mental health outcomes nor did they demonstrate a higher suicide rate. These findings are …