People with chronic traumatic encephalopathy (CTE) and a family history of mental illness may be at higher risk for aggression in midlife, according to a study published in the Nov. 27, 2024, online issue. Neurology®the medical journal of the American Academy of Neurology.
CTE is a neurodegenerative disease associated with repetitive head injuries, often seen in athletes and military personnel, and can lead to mood swings and dementia.
This appears to be a case where these risk factors together pose a greater risk of aggression than either alone, with people with CTE and a family history of mental illness being much more likely to engage in aggressive behavior than people with just CTE or just the family history.”
Jesse Mez, MD, MS, Chobanian & Avedisian School of Medicine, Boston University
The study involved 845 men who were exposed to repetitive head impacts through contact sports or military service. A total of 329 of them played professional football. All donated their brains for research after their death, which was at an average age of 60. Of the total group, 589, or 70%, had CTE and 383, or 45%, had a family history of mental illness.
Researchers interviewed family members or spouses of the participants about their aggressive behavior. It also asked whether participants’ parents, siblings, or children had ever been diagnosed with major depression, bipolar disorder, anxiety disorder, post-traumatic stress disorder, obsessive-compulsive disorder, or other mood or psychiatric disorders. If a family member had a diagnosis, the participant was considered to have a family history of mental illness.
Researchers then divided participants into four groups: 256 people, or 30%, with CTE and a family history of mental illness; 333 people, or 40%, with CTE and without a family history of mental illness; 127 people, or 15%, without CTE and with a family history of mental illness; and 129 people, or 15%, without CTE and without a family history of mental illness.
Researchers asked family members about participants’ aggressive behavior, such as whether they had violent arguments with others or gotten into physical fights, with scores ranging from zero to 44. They found that people with CTE and a family history of mental illness during the adulthood an average score of 19 compared to people with CTE without a family history of mental illness who had an average score of 17.
“This relationship was most striking for participants who died between the ages of 40 and 59,” Mez added.
After adjusting for other factors, such as total years playing contact sports and military history, researchers found that those who died between the ages of 40 and 59 with CTE and a family history of mental illness scored an average of 0.64 standard deviations higher on a scale called measuring aggression compared to people with CTE but without a family history of mental illness. For people who did not have CTE, having a family history of mental illness did not increase the risk of aggressive behavior.
“The link between a family history of mental illness and aggression may stem from a shared genetic background, as well as a shared environment and common behavior, such as childhood experiences with family members,” Mez said. “Identifying people who are more likely to exhibit symptoms of aggression based on family history of mental illness would give us a way to predict the consequences of CTE and identify who could benefit most from treatment options.”
A limitation of the study was that the study relied on past information from family members and spouses who may not have accurately remembered the information.
The study was funded by the National Institutes of Health, Department of Veterans Affairs and the Nick and Lynn Buoniconti Foundation.
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The American Academy of Neurology is the world’s largest association of neurologists and neuroscientists, with more than 40,000 members. The AAN’s mission is to improve members’ career fulfillment and promote brain health for all. A neurologist is a doctor with specialized training in diagnosing, treating, and managing disorders of the brain and nervous system, such as Alzheimer’s disease, stroke, concussion, epilepsy, Parkinson’s disease, multiple sclerosis, headaches, and migraines.
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