Associations between concussion and risk of diagnosis of psychological and neurological disorders: a retrospective population-based cohort study

Morissette MP, Prior HJ, Tate RB, Wade J and Leiter JRS. Fam Med Com Health 2020;8:e000390.
Full Text Freely Available

Take-Home Message

Someone with a history of concussion had a greater risk of attention deficit hyperactivity disorder, mood and anxiety disorders, dementia, or Parkinson’s disease than someone without a concussion.


Prior reports that someone with a history of a concussion is more likely to have attention deficit hyperactivity disorder (ADHD), mood and anxiety disorders, dementia, or Parkinson’s disease are limited by a small number of participants and recall bias. Therefore, the authors used health records from the Province of Manitoba in Canada between April 1990 and March 2015 to test if a concussion increases the risk of ADHD, mood and anxiety disorders, dementia, or Parkinson’s disease. The authors found 47,483 individuals (41% female; ~36 years of age) with a diagnosed concussion using International Classification of Diseases codes. Then, the authors matched each person with a concussion to 3 healthy controls based on age, sex, and geographical location. Finally, the authors determined if someone received a diagnosis of ADHD, mood and anxiety disorders, dementia, or Parkinson’s disease after a concussion (matched date for the healthy controls).

During follow-up, someone with a concussion had an increased risk of a diagnosis of ADHD (1.4 times), mood and anxiety disorders (1.7 times), dementia (1.7 times), and Parkinson’s Disease (1.6 times). Concussed women had a higher risk of ADHD and mood (28%) and anxiety disorders (7%) compared with concussed men. The authors also found that a second concussion further increased the risk of dementia, and having 3 or more concussions increased the risk of mood and anxiety disorders.


The authors of this 25-year retrospective longitudinal study found an association between a history of concussion and diagnosis of ADHD, mood and anxiety disorders, dementia, or Parkinson’s disease. The authors found these relationships even after controlling for socioeconomic status and overall health status. It is important to note that due to the retrospective research design, the specific mechanisms for this relationship remain unknown. For example, future research may clarify if a concussion may directly contribute to a person’s chance of getting dementia or if someone likely to develop dementia may have a susceptibility to a concussion (e.g., a genetic predisposition). If concussions have a direct impact on these future diagnoses, then it may be interesting to learn if how a person manages a concussion influences their risk of one of these conditions. Currently, medical professionals should be aware of this possible risk, educate at-risk populations, and have proper evidence-based protocols and management plans to enhance patient care to have positive outcomes later in life.

Questions for Discussion

Are you aware of your athletes with ADHD? Do you ask or take into consideration whether or not they are being treated for ADHD in your concussion diagnosis or return to play plan?

Written by: Jane McDevitt
Reviewed by: Jeffrey Driban

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