Knowing What We Don't Know: Long-Term Psychiatric Outcomes following Adult Concussion in Sports.

Objective: Amidst a growing concern regarding concussion in sports, there is an emerging link between sport concussion and mental health outcomes. This review summarizes the current literature addressing long-term psychiatric sequelae associated with sport concussion in adults.

Method: Several databases were searched using a broad list of keywords for each of concussion, sports, and mental health, with a resultant 311 studies for initial review. After limiting studies based on duplication, appropriateness of data, and relevance, 21 studies remained pertaining to depression, anxiety, substance use, and behavioural changes, including those highlighting chronic traumatic encephalopathy (CTE).

Results: Most studies identified suggested an increased prevalence of depressive symptoms related to concussion history. A conference abstract and qualitative study suggested increasing anxiety related to concussion history; however, a PhD dissertation found no relationship. In reviewing substance use, several studies mentioned use in athletes suspected of having concussion histories, although no link was established, while another noted undiagnosed concussion as leading to current substance misuse. Regarding behavioural changes, all studies identified occurrences of behaviour and/or cognitive changes in participants, with 2 studies suggesting a link with concussion history. With respect to CTE, concerns with mood, behaviour, cognition, and substance use were consistently highlighted, suggesting relations to previous sport concussion; however, the notion of different CTE subtypes and clear aetiology behind concussion severity or frequency was not consistently elucidated.

Conclusion: There appears to be a growing body of evidence supporting the presence of long-term psychiatric and psychological sequelae following sport concussion in adults.