Results from an eight-year study confirm that young people who have sustained a head injury are more likely to engage in violent behavior.
Researchers from the University Of Michigan School Of Public Health discovered that young people who suffered a recent head injury (within a year of being questioned for the study) were even more likely to report violent behavior.
By looking at young adults over an eight-year period, researchers were able to track the effects of the head injury in a general population. Before, most similar studies were conducted in prison populations.
The current study appears in the journal Pediatrics.
Head injuries range along a continuum from athletic concussions to traumatic brain injury suffered in war or a result of an accident. This study looks at head injuries from a broad perspective and confirms previous findings about the connection between violence and head injuries, said lead author Sarah Stoddard, Ph.D.
“These are not necessarily sports-playing injuries,” said Stoddard, who also is a research fellow at the U-M School of Nursing. “They could be from a car accident or from previous violent behavior, but it does support some of the sports research that’s been going on with concussions.”
The researchers followed a group of ninth-graders from four schools in Flint, Mich., into young adulthood. They conducted annual interviews over eight years. In years five and six, participants were asked if they had ever sustained a head injury. Those who said yes—about 23 percent—reported more violent behavior in year eight of the study.
Researchers studied the timing between a head injury and violent behavior and found that an injury reported in year seven of the study predicted violent behavior in year eight.
“We found that the link between a head injury and later violence was stronger when a head injury was more recent, even after controlling for other factors including previous violent behavior,” Stoddard said.
The results also suggest that adolescents and young adults who have suffered a head injury that did not interfere with their ability to participate in an hour-long interview may still experience significant adverse developmental or behavioral effects.
The researchers defined a head injury as having been knocked unconscious or sustaining a concussion or a fractured skull.
An estimated 1.7 million people annually sustain a TBI, and that only includes those who get medical care, so the number is likely much higher. Roughly 75 percent of head injuries are mild and many do not receive medical attention, but any TBI disrupts the function of the brain.
Long-term impact can include changes in cognition, language and emotion, including irritability, impulsiveness and violence.