Is There a Link Between Traumatic Brain Injuries and Violence?

Traumatic brain injuries (TBIs) are startlingly common in the United States. Every day, 153 people die from TBI-related injuries. When the brain sustains a serious injury, it can disrupt the brain’s normal functioning. Blows, jolts, puncture wounds, or other injury to the brain can alter memory, cognitive function, behavior, and mood. Now, studies are showing a possible link between traumatic brain injury and an increase in violence, aggression, and impulsivity.

Evidence of a Link Between Brain Damage and Violence

The brain is a complex organ. It is the central organ of the nervous system and in charge of controlling almost all the activities of the body. When the brain sustains damage, it can interrupt any number of physical and cognitive processes. Many doctors and scientists are still learning about brain injuries. The symptoms of TBIs can be unpredictable and vary greatly from person to person. Recently, studies have shown ties between concussions and violence. One example is the brain scans of former NFL player Aaron Hernandez.
Hernandez went to prison in 2013, serving life for murder. He committed suicide in his cell in 2017. Recently, his attorneys revealed that Hernandez suffered from advanced chronic traumatic encephalopathy (CTE). CTE is a kind of brain damage from repeated trauma to the head that can lead to symptoms such as depression, violence, and mood swings. Scans of Hernandez’s brain showed levels of CTE typically present in much older football players (Hernandez was 27 at the time of death). The findings were consistent with other CTE diagnoses in the brains of over 100 former NFL players.
Studies of brain injuries in convicted criminals have shown that those with a history of TBIs are more likely to engage in violent behaviors. Dr. Stoddard of the University of Michigan conducted a study of 850 high schoolers who had grade point averages of three and lower. She found that 88 of them had suffered head injuries, and 43% of the 88 had been in fights or participated in violence in the past years, compared to 34% who did not report head injury. While the brain can recover over time, people living with head injuries can be prone to violent acts shortly after the injury occurs.

Concussive Brain Injury and Neurological Problems

One of the most common symptoms after suffering a traumatic brain injury is aggression. According to one study, 28.4% of participants with first-time TBIs exhibited verbal aggression. Prevalence of aggression in TBI patients range as high as 34% in some cases. The correlates of post-TBI aggression include depression, poor psychosocial functioning, frontal lobe lesions, behavioral problems, and substance abuse.
CTE and violent behavior appear to go hand in hand according to several years of research on the subject. While the connection remains not clearly understood, there is enough data regarding people with TBIs – particularly NFL players who have suffered multiple brain injuries – to show a link between brain injury and violence. NFL player arrest rates for violent crimes are much higher than other demographics would predict. While steroids, underlying mental health problems, and a propensity for taking risks might also contribute, many researchers strongly believe repetitive TBIs play a major role in violent behaviors post-brain injury.