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A recent study published in the journal Deviant Behavior suggests that professional football players with a history of documented concussions experience higher odds of being arrested than players without such a medical history. These findings provide preliminary evidence that brain injuries sustained in high-impact sports might be associated with later interactions with the criminal justice system.
A traumatic brain injury is a type of damage to the brain that affects its normal functioning. These injuries often result from a violent blow or jolt to the head, or from a rapid acceleration and deceleration of the body. This rapid movement causes the brain to bounce around or twist in the skull, creating chemical changes and sometimes stretching and damaging brain cells.
Medical professionals recognize that these physiological changes in the brain can increase the likelihood of certain behavioral issues. Specifically, damage to the frontal and temporal lobes of the brain, which are the areas responsible for decision-making and emotion, tends to reduce impulse control and limit a person’s ability to inhibit aggressive actions.
Prior studies linking brain injuries to behavior highlight increased risks of violent crime among affected populations. Some individuals with brain injuries struggle with emotional regulation and impulse control. Impulsivity is characterized by a lack of premeditation and an increase in risk-taking behaviors. This lack of self-regulation can sometimes lead to actions that violate laws and result in police contact.
High-impact sports populations present an opportunity to explore these associations in greater detail. National Football League players experience a disproportionately high incidence of head trauma compared to the general public. The cumulative toll of repetitive head impacts can result in conditions like Chronic Traumatic Encephalopathy. This progressive brain disease is associated with a history of repeated head injuries and is characterized by a gradual shrinking of the brain and enlargement of its fluid-filled spaces.
The authors of the new paper sought to clarify this relationship by examining whether officially documented concussions influence the likelihood of a player facing formal police booking. “The motivation for this research came from an empirical gap I saw in NFL criminology research,” said lead author Jackson Perry, an incoming doctoral student in criminal justice and criminology at Florida State University. He co-authored the paper with Kimberly Kras and Burrel Vann Jr., both professors in the School of Public Affairs at San Diego State University.
Perry noticed that public conversations about concussions, brain disease, and player arrests often happen in separate lanes. “Much of the work on NFL players in criminology and public health has treated concussions and arrests as separate issues, even though both touch on player health, behavior, and long-term support,” Perry explained. “Public conversations about NFL concussions, CTE, and player arrests often happen in separate lanes, and when they overlap, they can become speculative very quickly.”
He pointed out that these overlapping issues require formal study. “I wanted to bring a criminological lens to that overlap and ask a direct empirical question: in the available public data, are documented NFL concussions associated with booking-based arrest outcomes?” Perry noted. “To me, the larger issue is that brain health should be part of how we think about player support during and after football, not just during the immediate injury window.”
To explore this topic, the researchers built a unique dataset using several publicly available sources. They focused on a massive sample of 6,201 professional football players who appeared in at least one regular season game between 2010 and 2020. They gathered weekly injury reports from statistical databases across this eleven-year period to identify players who had suffered at least one officially documented concussion.
A concussion is a mild form of traumatic brain injury that temporarily interferes with brain function. Because players can suffer multiple head injuries over a career, the researchers took steps to measure distinct injury events accurately. They coded a new concussion episode only if it occurred more than two weeks after a previous injury notation, excluding bye weeks. This step helped balance the data and prevent overcounting single injuries that simply kept a player on the injury report for multiple consecutive weeks.
For their primary outcome, the scientists tracked booking-based arrests from January 2010 through December 2024. They utilized a well-known public arrest database maintained by USA TODAY, which tracks legal incidents involving professional football players. The researchers specifically defined an arrest as an event where a player was formally taken into custody and booked into jail or surrendered to authorities for booking. They excluded incidents where players were only issued a citation, briefly detained without a formal booking, or had warrants rescinded.
When an arrest event included multiple charge descriptors, the researchers assigned a single offense category using a severity hierarchy. Violent offenses were ranked highest, followed by property offenses, public order offenses, and criminal justice-related offenses. This coding system allowed the researchers to look at overall arrest trends as well as the specific rates of violent arrests.
The researchers found that 942 players, or about 15.2 percent of the study sample, had at least one documented concussion during the eleven-year observation window. Meanwhile, arrests were relatively uncommon overall. Only 345 players, or 5.6 percent of the sample, experienced a booking-based arrest during the study period. When analyzing the statistical relationship between these two factors, the authors discovered that concussion exposure was associated with a higher prevalence of arrest.
“The effect was meaningful, but it should be interpreted in context,” Perry said regarding the statistical differences. “In the unadjusted model, the predicted probability of any arrest was about 5.2% for players without a documented concussion and about 7.6% for players with a documented concussion, an absolute difference of roughly 2.5 percentage points. That difference is large enough to raise a serious question: are we doing enough to understand and support players after repeated exposure to head impacts?”
The researchers also looked specifically at violent arrests as a secondary outcome. They noted a similar pattern in the raw numbers, with 2.3 percent of concussed players facing a violent arrest compared to 1.5 percent of non-concussed players. However, this specific association for violent offenses did not reach statistical significance. This means the mathematical difference was not large enough to rule out random chance as the cause.
An important nuance emerged when the researchers looked at the timing of the arrests and the injuries. They ran a secondary test that excluded cases where a player’s first arrest occurred before their first documented professional concussion, and the association was no longer statistically significant in this restricted test. “What stood out most was how much timing shaped the story,” Perry noted.
“The association appeared in the main unadjusted analyses and remained when arrests were restricted to the 2010 to 2020 observation window, but it did not hold under the stricter test that excluded cases where the earliest arrest came before the earliest documented NFL concussion,” Perry told PsyPost. This sensitivity to temporal ordering suggests that early-life head trauma prior to joining the professional league might be influencing the broader patterns.
“That does not make the issue less important,” he said. “It shows why this topic needs stronger life-course data. Many players begin football years before the NFL, so the first documented NFL concussion may capture only one piece of a much longer history of head-impact exposure.”
The authors provide a few warnings against misinterpreting these results as a direct cause-and-effect relationship. “The main misinterpretation I want to prevent is the idea that this study proves concussions cause arrests or violent behavior,” Perry cautioned. “It does not. What we found is an association in observational data, and documented NFL concussions capture only part of a player’s total head-impact history, not every concussion, subconcussive hit, pre-NFL injury, injury severity, or recovery process.”
Despite these limitations, the findings highlight a need for ongoing attention to player well-being. “At the same time, caution should not become complacency,” Perry added. “The pattern we found fits with broader concerns about traumatic brain injury, behavioral regulation, and long-term functioning. For a league built around repeated physical contact, this should be treated as a player-support issue, not just a discipline issue.”
The models used in the study were unadjusted, meaning they did not account for demographic factors like socioeconomic status, income, or education level. Additionally, the researchers could not account for a player’s field position. A player’s position might influence both the risk of getting a concussion and their general behavioral tendencies, making it an important factor to consider in future work. The reliance on official injury reports also means that undiagnosed concussions were not captured in the data.
The researchers suggest that the findings have immediate relevance for how sports organizations handle player safety. “The main takeaway is that head injury is relevant to behavioral health and criminal justice contact in ways we should take seriously,” Perry said. “In our study, NFL players with documented concussions had higher odds of booking-based arrest in unadjusted analyses. That should not be read as saying concussions make people criminal.”
Instead, the data points to a complex intersection of health and behavior. “It means brain health, behavior, and justice-system contact can intersect in high head-impact populations, and that intersection deserves better data, better monitoring, and stronger long-term support for players,” Perry stated. Better access to counseling and psychological services during recovery might help support players who experience changes in emotional regulation and impulse control after an injury.
Looking ahead, the researchers hope to build on this foundational work. “My long-term goal is to better understand how head injury, behavioral regulation, and criminal justice contact intersect, especially in populations with repeated exposure to head impacts,” Perry said. “For this topic, the next step is stronger longitudinal research that can better capture lifetime head-injury exposure, position played, years of football exposure, concussion severity, pre-NFL criminal justice contact, and post-career outcomes.”
The authors also advocate for a shift in how sports leagues approach these challenges. “I also think future work should move beyond asking only how the league responds after misconduct occurs,” Perry explained. “A stronger long-term model would focus more directly on prevention, post-injury monitoring, behavioral health support, and transition care after players leave the league. If head injury can affect sleep, mood, impulse control, or emotional regulation, support systems should be built around those risks before they become crises.”
In the end, the study calls for a more comprehensive approach to player health. “I see this study as part of a broader argument that player safety has to include long-term brain health, not just what happens on the field or inside the concussion protocol,” Perry said. “Professional football is a high head-impact environment, and players should not be left to navigate the possible aftereffects of that exposure on their own.”
The researchers hope their work sparks meaningful changes in the sporting world. “The league has the resources to think about player well-being across the full career arc: before injury, after injury, and after retirement,” Perry concluded. “My hope is that this study encourages a conversation about support, prevention, and long-term care, not just punishment after something goes wrong.”
The study, “Headstrong, Flagged Later: Concussions and Arrest Risk Among NFL Players,” was authored by Jackson Perry, Kimberly Kras, and Burrel Vann Jr.