Systematic review of mental health measures associated with concussive and subconcussive head trauma in former athletes.

Public concern has been a catalyst for an emerging body of research investigating the potential long-term negative health consequences associated with sport-related concussion and subconcussive impacts. We conducted a systematic review of the literature on mental health measures associated with sport-related brain injuries in former athletes. Ovid MEDLINE, EMBASE, CINAHL, and PsychINFO databases were used. Thirteen studies were included in the final review. We identified a consistent positive association between a history of concussion and depression among former athletes, although the underlying causation remains unclear. Limited and inconsistent findings were observed in studies that evaluated subconcussive impacts. Overall, several methodological shortcomings were noted, including selection bias, research design, operational definitions, and measurement tools. Future research will benefit from employing prospective longitudinal studies, surveillance data systems and standardized collection methods, and should attempt to account for psychosocial modifiers or confounders when reporting the mental health status of former athletes. This area would also benefit from studies that include equal representation of male and female athletes, examine mental health disorders beyond depression, and assess a variety of sports and competition levels.