If you look at any list of symptoms for chronic traumatic encephalopathy, the neurodegenerative brain disease associated with repeated brain injuries, you are fairly likely to see violent outbursts among others such as cognitive decline, memory problems, and mood changes such as depression or anxiety.
It seems fair enough, as many of the professional athletes who have been recently diagnosed with CTE post-mortem had behavioral problems including violence before their death. However, a recent article from the New Republic suggests the association may not be so simple.
Naomi Shavin spoke with Dr. Alison Brooks of the University of Wisconsin Madison, who pointed out that many football players are prone to high-risk behavior from the very start. Obviously, this plays a role in leading them to choose to be football players, but it also tends to make players more inclined towards drugs, alcohol, and aggressive behavior. Even when you factor in CTE, numerous factors such as steroid or drug use and pre-existing mental health issues could also facilitate violent behavior.
Other medical professionals have also been hesitant to distinguish a direct link between CTE and violent behavior. Dr. Michael Wolf, a pediatrician specializing in sports medicine at St. Christopher’s Hospital for Children in Philadelphia and on the faculty at Drexel University School of Medicine told Shavin, “in medicine we’re very resistant to make big claims on isolated events.”
On the other hand, there are several studies suggesting there may be more to the association than outside factors and isolated events. Several studies have examined the high rates of brain injuries among prison populations, and rates of brain injury are believed to be almost 100% among death row inmates. Additionally, a 1996 report found that Vietnam War Veterans who suffered penetrating brain injuries with damage to a particular part of the frontal cortex were more prone to aggression.
Ultimately, this is just one of many questions still not thoroughly answered by our current understandings of traumatic brain injury and chronic traumatic encephalopathy. While we have a lot of information at our fingerprints, there is still a long way to go before we really understand these conditions and can treat them properly.