Washington: A new study has found that adolescent boys who are hurt in just two physical fights suffer a loss in IQ that is roughly equivalent to missing an entire year of school.
Girls experience a similar loss of IQ after only a single fighting-related injury.
The findings are significant because decreases in IQ are associated with lower educational achievement and occupational performance, mental disorders, behavioral problems and even longevity, the researchers said.
"It`s no surprise that being severely physically injured results in negative repercussions, but the extent to which such injuries affect intelligence was quite surprising," Joseph A. Schwartz, a doctoral student who conducted the study with Professor Kevin Beaver in Florida State University`s (FSU) College of Criminology and Criminal Justice, said.
The study is among the first to look at the long-term effects of fighting during adolescence, a critical period of neurological development.
About 4 percent of high school students are injured as a result of a physical fight each year, the researchers said.
Perhaps not surprisingly, boys experienced a higher number of injuries from fighting than girls; however, the consequences for girls were more severe, a fact the researchers attributed to physiological differences that give males an increased ability to withstand physical trauma.
The researchers found that each fighting-related injury resulted in a loss of 1.62 IQ points for boys, while girls lost an average of 3.02 IQ points, even after controlling for changes in socio-economic status, age and race for both genders.
Previous studies have indicated that missing a single year of school is associated with a loss of 2 to 4 IQ points.
The impact on IQ may be even greater when considering only head injuries, the researchers said.
The study is published in the Journal of Adolescent Health.