There are numerous factors that influence an individual’s behavior and researchers and social scientists often attempt to discover why some people engage in acts of violence. While factors like an individual’s upbringing, life experiences and even genetics all likely play a role, a recent Australian study also reveals that individuals who engage in violent and criminal behaviors are also more likely to have suffered a traumatic brain injury.

For the study, researchers examined more than 136,000 individuals between the ages of 30 and 35. Of study participants, 7,694 had suffered at least one TBI. Overall, researchers noted that these individuals were twice as likely to have a criminal conviction and to suffer from a mental illness.

Of those men who reported suffering a TBI, the average age of a first TBI was 10 years old and for women, the average age was 7 years old. The Criminal conviction rate among men who suffered TBIs was roughly 18 percent compared to 10 percent for men with no history of a brain injury. Among women, conviction rates for non-TBI sufferers was just four percent while, at nine percent, conviction rates among women who reported suffering at least one TBI more than doubled.

Along with incarceration rates, the rate of mental illness among male TBI sufferers was 19 percent versus nine percent for men with no brain injuries. For women, the rates of mental illness were 22 percent for those who suffered a brain injury and 13 percent for those who had not.

The findings of this study are noteworthy and help illustrate the many, adverse and long-term effects of a brain injury. TBIs have been linked to an increase in aggressive and violent behaviors and a significant percentage of TBI sufferers also develop depression and struggle with other mental health issues.

Source: Medical Daily, “Traumatic Brain Injury And The Crime Rate: Offenders Have Higher Rates of Past TBIs,” Susan Scutti, July 20, 2015