Traumatic Brain Injury: The True Culprit?

By Jackie Man

Over the past century, the invention of fingerprint technology and DNA has revolutionized the way law enforcement investigates crime and how victims are perceived. In fact, neuroscience suggests that common victim responses are actually the product of anxiety and trauma (Wilson et al., 2016). Traumatic brain injury (TBI) is the biggest cause of death and disability in children and young people, and continues to be a major public health problem around the world. It affects major neural mechanisms associated with self-regulation and social behavior, increasing the risk of behavioral disorder and psychiatric morbidity, resulting in higher risks of committing criminal violence (Williams et al., 2018). 

The correlation between TBI and both violent and non-violent criminal activity has been shown by several studies. For instance, Sarapata et al. recorded that 50% of people with TBI were accused of non-violent or minor offences, compared to the 5-15% amongst those without TBI (Sarapata, Herrman and Johnson, 1998). Another study found that 12 out of 16 death row prisoners have a history of brain injury, mostly attributable to multiple insults originating from child abuse (Freedman and Hemenway, 2000). All of these studies independently suggest  a clear relationship between TBI and an act of violence and crime. So, is TBI really the true culprit of crime? Prior to determining whether TBI is the true cause of crime, the concept of TBI must first be understood. 

Traumatic brain injury (TBI) is a broad term that describes a vast array of injuries that damage the brain, usually resulting from external mechanical forces. Common injuries that cause TBI include motor vehicle accidents, violence, falls, or child abuse. These injuries can potentially lead to lacerations and bruising of internal brain structures, especially near the bony protrusions on the basal surface of the skull, due to a mechanism called croup-countercoup (Traumatic Brain Injury, 2020). The jarring of the brain against the insides of the skull, shearing of the internal lining, muscles and blood vessels can lead to internal bleeding and secondary hypoxia. The capacity for loss of axonal connectivity is common in milder injuries; while in more severe injuries, damage in the frontal and temporal regions of the brain and the shearing of white matter tracts could lead to lifelong disabilities and are likely to be associated with antisocial and criminal behaviors (Turkstra, Jones and Toler, 2002).

This damage to the brain usually occurs to the frontal lobes of the brain – more specifically, to the prefrontal cortex. This region of the brain, which is damaged frequently in the case of TBI, is located on the front part of the frontal lobe and is responsible for an individual’s will to live, cognitive behavior, decision making, social behavior, executive function and personality expression (Liang, 2020). In other words, it limits the ability to control impulsive, aggressive feelings, encouraging risk-taking, rule-breaking, and emotional and aggressive outbursts. If damage were to happen in these regions, lesions may impair functions such as social cognition, self-regulation and judgement, as well as emotions and mood, which is often associated with a lack of control over subcortical and limbic systems involved with primitive impulses (Turkstra, Jones and Toler, 2002). As a result, the correlation between brain injury (TBI) and crime may be due to the behavioral consequences of TBI-related cognitive and emotional impairments (Turkstra, Jones and Toler, 2002).

The changes in behavior due to TBI was investigated in studies conducted by Max et al., evidencing how damage to the prefrontal cortex due to TBI can interrupt the development of social interaction processes and lead to behavioral changes and problems. The study tracked 94 post-TBI children 5-14 years following the incident responsible for their TBI and accessed their personality changes (PC) within the five subtypes, classified as effectively liable, aggressive, disinhibited, apathetic and paranoid. Findings showed that 59% of those with severe TBI and 5% with mild/moderate TBI experienced a personality change, prominently in emotional lability, aggressive and disinhibition (Max, Levin and Landis, 2001). In a related study, it was also found that in the first six months after TBI injury, personality changes occurred in 22% of patients and that most of these changes were found on patients with lesions on the dorsal prefrontal cortex, primarily the superior frontal gyrus, associated with a shift in personality (Max et al., 2006). 

In addition to these findings, a more recent study also showed that behavior post-TBI could have detrimental effects on key social roles. In the study, young adults at risk of high school dropout were investigated, and it was found that those who had experienced head injury before young adulthood were associated with more interpersonal violence (i.e. alcohol use, drug use, delinquency and aggression behavior), compared to those participants who never had a head injury (Stoddard and Zimmerman, 2011). In the study, in addition to showing the relationship between head injury and interpersonal violence, they also showed that the relationship between head injury and violence was stronger depending on how recent the injury was (Stoddard and Zimmerman, 2011). These data, along with the findings of previous studies, showed how there is a linked history of TBI to later violent behavior: damages to the dorsal prefrontal cortex, as mentioned above, could lead to mid to long term changes to behavior, potentially leading to criminal behavior. 

Alternatively, some view the link between TBI and crime as an epiphenomenon, arguing that TBI only serves as a secondary effect in addition to the underlying demographic variables that influence criminal behavior. It was suggested that both criminal behavior and TBI are the product of dynamic associations between genetic and environmental factors, including emotional stress, poverty and child abuse. It was believed that people living in poor and violent settings would not be given the opportunity to develop prosocial habits and thus would be more likely to commit offences later in life, increasing the likelihood of getting a brain injury. Further, among individuals who suffered from TBI, it was shown that prior to their impulsive aggression post-injury, most already had pre-morbid antisocial habits. This indicates the impulsive and violent behaviors of the individuals may have been further disinhibited by TBI, but were not solely attributable to TBI. (Turkstra, Jones and Toler, 2002) This was shown in a study conducted by Raine et al. In the study, despite half of the participants having a history of TBI, variants in brain activity were mainly correlated with childhood trauma and child abuse, and TBI was not deemed an important factor (Raine et al., 2001).  

To answer the question, TBI appears to be associated with increased risk of violence and conviction, and may be a potential cause of crime. Through understanding the neurobiology of TBI as well as the findings of different studies, it is not surprising that the association between TBI and offending has become an important consideration during the investigation of criminal justice. However, due to the need to consider other important environmental and demographic factors, more research and studies have to be done in order to clarify the direction of the relationship between TBI and offending behavior, and its associations with crime. 


Department of Neurology. 2020. Traumatic Brain Injury. [online] Available at: <; [Accessed 17 November 2020].

Freedman, D. and Hemenway, D., 2000. Precursors Of Lethal Violence: A Death Row Sample. [online] ScienceDirect. Available at: <; [Accessed 17 November 2020].

Liang, A., 2020. Research Review On Traumatic Brain Injury In The Criminal Justice System. [online] Available at: <; [Accessed 17 November 2020].

Max, J., Levin, H., Schachar, R., Landis, J., Saunders, A., Ewing-Cobbs, L., Chapman, S. and Dennis, M., 2006. Predictors Of Personality Change Due To Traumatic Brain Injury In Children And Adolescents Six To Twenty-Four Months After Injury. [online] Available at: <; [Accessed 17 November 2020].

Max, J., Levin, H. and Landis, J., 2001. The Phenomenology Of Personality Change Due To Traumatic Brain Injury In Children And Adolescents | The Journal Of Neuropsychiatry And Clinical Neurosciences. [online] Available at: <; [Accessed 17 November 2020].

Raine, A., Park, S., Lencz, T., Bihrle, S., LaCasse, L., Widom, C., Al-Dayeh, L. and Singh, M., 2001. Reduced Right Hemisphere Activation In Severely Abused Violent Offenders During A Working Memory Task: An Fmri Study. [online] Available at: <; [Accessed 17 November 2020].

Sarapata, M., Herrman, N. and Johnson, D., 1998. The Role Of Head Injury In Cognitive Functioning, Emotional Adjustment And Criminal Behaviour. [online] Available at: <; [Accessed 17 November 2020].

Stoddard, S. and Zimmerman, M., 2011. Association Of Interpersonal Violence With Self-Reported History Of Head Injury. [online] Available at: <; [Accessed 17 November 2020].

Turkstra, L., Jones, D. and Toler, H., 2002. Brain Injury And Violent Crime. [online] ResearchGate. Available at: <; [Accessed 17 November 2020].

Williams, W., Chitsabesan, P., Fazel, S., McMillan, T., Hughes, N., Parsonage, M. and Tonks, J., 2018. Traumatic Brain Injury: A Potential Cause Of Violent Crime?. [online] Available at: <; [Accessed 17 November 2020].Williams, W., Chitsabesan, P., Fazel, S., McMillan, T., Hughes, N., Parsonage, M. and Tonks, J., 2018. Traumatic Brain Injury: A Potential Cause Of Violent Crime?. [online] Available at: <; [Accessed 17 November 2020].

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