Traumatic brain injury has anecdotally been tied to behavioral problems and issues with impulse control for decades, but the relationship between concussions and risk-taking has largely been ignored.
Now, a team of researchers from the University of British Columbia has found scientific evidence that even mild traumatic brain injuries (often called concussions) can lead to impulse control issues using a study of rats.
According to the study published in the Journal of Neurotrauma, an inflammatory molecule in the brain related to mild traumatic brain injury may be tied to impulsivity levels. The team also believes the molecule could be a useful target for potential future treatments.
“Few studies have looked at whether traumatic brain injuries cause impulse control problems,” said the study’s lead author, Cole Vonder Haar, a former postdoctoral research fellow in the UBC department of psychology who is now an assistant professor at West Virginia University. “This is partly because people who experience a brain injury are sometimes risk-takers, making it difficult to know if impulsivity preceded the brain injury or was caused by it. But our study confirms for the first time that even a mild brain injury can cause impulse control problems.”
In the study, the team of researchers gave brain injured rats a reward test to measure impulsivity. Those that choose a small reward rather than wait for a larger reward were considered more impulsive.
According to the findings, impulsiveness increased in all rats with brain injuries – regardless of the severity of the brain injury. Increased impulsiveness was also seen for up to eight weeks after the injury in the rats with a mild brain injury, even after memory and motor function symptoms had faded away.
“These findings have implications for how brain injury patients are treated and their progress is measured,” said Vonder Haar. “If physicians are only looking at memory or motor function, they wouldn’t notice that the patient is still being affected by the injury in terms of impulsivity.”
The researchers then compared these findings against samples taken from the frontal cortex of brain tissue. They found that rats with increased impulsivity also showed notably heightened levels of an inflammatory molecule called interleukin-12.
The findings could have substantial implications for future treatment of traumatic brain injury. Most concussion treatments have no method to address many of the psychological symptoms of the injury. This can leave those with concussions at increased risk for substance abuse or issues with addiction.
Catharine Winstanley, the senior author of the study and associate professor in the UBC department of psychology, believes targeting the inflammatory molecules tied to these issues with impulse control could potentially prevent substance abuse or other related issues.
“Addiction can be a big problem for patients with traumatic brain injuries,” she said. “If we can target levels of interleukin-12, however, that could potentially provide a new treatment target to address impulsivity in these patients.”