The acute and long-term effects of repeated sub-concussive impacts on mental health of athletes: a narrative review

INTRODUCTION & AIMS Sub-concussive impacts—traumatic blows to the head that fail to present clinically as concussions—may be contributing factors that lead to long-term negative health consequences seen in athletes, including cognitive and emotional disturbances. The aim of this project is to consolidate the current body of literature examining the relationship between sub-concussive impacts and mental health in athletes via a narrative review examining the acute and long-term effects of sub-concussive impacts in athletes. METHODS Two undergraduate research cadets assisted the research team with identifying and organizing relevant literature in the topic area. This systematic search was first conducted in April 2023 with a final search conducted in August 2023 using a combination of manual searching and databases (e.g., PubMed). Studies were saved and exported to Excel for further analysis. Inclusion criteria included the need for the study to have been conducted in an athletic population with mental health outcomes being surveyed as a result of concussion or sub-concussion head impacts. Components of the articles were documented in an Excel spreadsheet with considerations for year of publication, country of origin, study design, sport, and purpose of study. RESULTS Fifty-seven studies were thoroughly reviewed via a full-text analysis to determine whether inclusion criteria were met. Six studies were included in the final review. Despite a consistent positive association between history of concussion and depression being identified, limited and inconsistent findings were observed in studies evaluating sub-concussive impacts. Definitions varied for what constituted a sub-concussive head injury, further diluting the availability of high-quality research in this topic area. CONCLUSION This narrative review has identified a limited amount of research conducted on the impact of sub-concussive head injuries on the mental health of athletes. This warrants further investigation as the implications of concussion and sub-concussive head impacts continue to affect the lives of athletes everywhere.