(RxWiki News) They say that "boys will be boys" when the roughhousing gets too rough. Yet both boys and girls get into serious fights during their teen years. And the effects could last well beyond graduation.
A recent study found that teens may experience a small drop in IQ points for each serious injury they receive from fights.
The decrease in intelligence was greater for the females than the males, though it's not clear why.
The study combined all injuries together so it could not distinguish between head injuries and other kinds of injuries.
"Teach your kids to avoid fights."
This study, led by Joseph A. Schwartz, MA, at the College of Criminology and Criminal Justice at Florida State University, looked at the possible impact of injuries from fighting on a child's intelligence.
The researchers used data collected between 1994 and 2002 from the National Longitudinal Study of Adolescent Health. This survey involved over 20,000 youth, aged 12 to 21 in the first wave, who came from 132 middle and high schools across the US.
The second wave a few years later included 15,000 youth who were also included in the first wave. Then a third wave occurred five years later (2001 and 2002), providing long-term data for the same teens.
The teens were asked at each of these survey follow-ups about personality traits, social relationships and certain behaviors.
One question asked how often in the previous year the teens had been in a physical fight in which they were injured and required treatment from a doctor or nurse.
This information was compared with an intelligence score (IQ) based on a picture vocabulary test that the participants took.
The 22 participants who reported being in more than 10 serious fights were not included in the analysis since they might have skewed the results.
The researchers took into account the participants' socioeconomic background (household income and education level), sex, age and race in their analyses.
Overall, 7.2 percent of the participants had been involved in at least one fight that resulted in serious injury. This group included 10.2 percent of the males surveyed and 4.5 percent of the females surveyed.
The researchers determined that "...each fighting-related injury resulted in a loss of approximately 1.89 IQ points even after controlling for changes in socioeconomic status, age, race and gender."
The loss in IQ points was different based on different sexes. Boys saw a drop of about 1.62 IQ points for each serious fighting injury, and girls saw a drop of about 3.02 IQ points for each one.
The researchers saw bigger drops in IQ over time for those involved in more fights.
"Fighting-related injuries have a significant impact on subsequent cognitive functioning and intelligence," the researchers concluded.
They also noted that one limitation of their study was that all fighting injuries were lumped together.
Therefore, the possible effects on IQ of a head injury compared to other types of injuries could not be separated out in this study. That also means, they said, that head injuries in particular may result in larger drops in IQ.
"Although adolescent fighting is generally discouraged, all too often it is viewed as 'boys will be boys' when in reality fighting may be promoting cognitive decline later in life," the authors wrote.
"These findings may also have implications for related sources of physical injury, such as contact sports," they wrote.
Glen Elliott, MD, PhD, a clinical professor at the Stanford University Department of Psychiatry and Behavioral Sciences, said fighting is certainly not a positive behavior, but he finds several limitations to this study.
“The authors have raised an alarming possibility that adolescents who engage in recurrent fighting that leads to serious injury may pay the price in the form of a marked reduction in IQ," he said.
"The authors assume that this effect is from head injury, although their data did not allow them to assess that," Dr. Elliott said.
"Certainly, as they note, it speaks to the importance of helping adolescents protect their relatively fragile, developing brains to the extent possible and suggests the need for serious attention to other ways they might have gotten head injury, including a variety of sports," he said.
"That said, there may be more of a two-way process going on than they imply, with a real possibility that adolescents with lower IQ, possibly caused by earlier injury, are more prone to subsequent fighting, strengthening the correlation,” Dr. Elliott said.
The study was published July 26 in the Journal of Adolescent Health.
The research was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development along with cooperative funding from 23 other federal agencies and foundations.
The authors declared no conflicts of interest.