Professional athletes get paid, and handsomely at that, for essentially being the physically best at what they do. For an NFL football player, these skills include very physical and often violent acts like hitting and tackling. While NFL players routinely see their careers end over shattered bones and dislocated shoulders, today the careers of at least two well-known players may be over as both face criminal charges related to acts of domestic violence.

A propensity for violence appears to be something many NFL players display both on and off the field. Recently, NFL running backs Ray Rice and Adrian Peterson were arrested and charged with crimes related to aggravated assault and child abuse. Statistics show that NFL players are roughly four times more likely to be arrested for acts related to domestic violence than the national average.

These alarming statistics have raised many concerns and lead some to question the role brain injuries may play in contributing to increased aggression in football players. All NFL football players have been hit, sacked and taken down numerous times in their careers. Within the last decade, several lawsuits filed by former players resulted in many studies on brain injuries in NFL players.

After sustaining possibly thousands of hard hits and jolts throughout their football careers, it’s highly likely that the vast majority, if not all, of NFL players have suffered brain injuries of some degree. Repeated brain injuries have been linked to permanent damage to the frontal portion of the brain. This area of the brain is responsible for regulating emotion and controlling behavior. In cases where damage has occurred, an individual is more prone to violent, aggressive and unrestrained acts and behaviors.

The NFL has also admitted that “almost 30 percent of NFL players will suffer from at least moderate neurodegenerative disease.” For example chronic traumatic encephalopathy or CTE is a degenerative disease in which suffers are prone to impulsiveness and aggression as the brain essentially deteriorates. Previous tests have linked players who suffered from CTE to increased acts of violence and domestic abuse.

The scientific evidence exists to link brain injuries with increased aggression and violence. In the coming months, we’ll continue to explore this topic and especially as it relates to the pending criminal charges against Ray Rice and Adrian Peterson.

Forbes, “Does Playing Football Make You Violent? Examining The Evidence,” Dan Diamond, Sep. 16, 2014