Concussion may increase risk of health disorders like dementia, Parkinson's disease and ADHD, find researchers
Concussion has been linked to an increased risk of subsequent hyperactivity disorder, dementia, Parkinson's disease as well as mood and anxiety disorders by researchers in a new study. They found that concussion was associated with a 72% heightened risk of developing dementia and a 57% increased risk of developing Parkinson's disease.
After taking account of potentially influential factors, including income, educational attainment and other coexisting health conditions, attention-deficit/hyperactivity disorder (ADHD) was 39% more likely in those who had been concussed, says the analysis published in the journal Family Medicine and Community Health. “Concussions are a potentially debilitating injury and have shown a steady increase in incidence over recent years — namely, in adolescents. The findings from this study demonstrate an association between the occurrence of concussion and an increased risk of a diagnosis of attention-deficit hyperactivity disorder, mood and anxiety disorders, dementia and Parkinson’s disease later in life,” write authors.
A concussion is a traumatic brain injury that affects brain function. While concussions are usually caused by a blow to the head, violently shaking of the head and upper body also can cause concussions. A concussion upsets the workings of the autonomic nervous system as well as blood flow to, and around, the brain. Those affected usually recover within a week of injury, but there may be long term consequences, according to experts.
In the current study, the authors analyzed medical health data for the province of Manitoba, Canada, between 1990-91 and 2014-15. They wanted to see if those who had been concussed were more likely to subsequently be diagnosed with ADHD, mood and anxiety disorders, dementia, or Parkinson's disease than those who had not been concussed. During the 25-year study period, 47,483 people (28,021 men, average age 25; and 19,462 women, average age 21) were diagnosed with a concussion. Each of them was compared with up to three other people, matched for age, sex, and geographic area, who had not been concussed (81,871 men and 57,159 women).
Compared with those who had not been concussed, those who had been were more likely to be diagnosed with various neurological or psychological disorders. The team also found that mood and anxiety disorders were 72% more likely, particularly among women, who were 28% more likely than men to subsequently become hyperactive and 7% more likely to become depressed/anxious after a concussion. “Concussion was associated with an increased risk of a diagnosis of ADHD (hazard ratio of 1.39), mood and anxiety disorders or MADs (1.72), dementia (1.72), and Parkinson's disease (1.57). Concussed women had a higher risk of diagnosis of ADHD and MADs by 28% and 7%, respectively, as compared with concussed men,” the findings state.
A second concussion further strengthened the association with the heightened risk of dementia, while three or more concussions strengthened the association with mood and anxiety disorders and Parkinson's disease. The findings indicated that a diagnosis of ADHD after concussion was more likely in younger people while a diagnosis of dementia and Parkinson's disease was more likely in older people. “But while the findings indicate that the conditions studied may be interlinked, concussion was still independently associated with ADHD, mood and anxiety disorders, dementia, and Parkinson's disease. As our results are specific to the administrative health data used for the present study, future studies exploring the relationships between concussion and attention-deficit/hyperactivity disorder, mood and anxiety disorders, dementia, and Parkinson’s disease in other populations are warranted,” recommends the team.