Study: Teenagers seriously injured in fight show reduction in cognitive ability

Teenagers who have been seriously injured in a fight show a reduction in intelligence and cognitive ability, according to a large study in the Journal of Adolescent Health.

"The results indicated that males suffer a loss in IQ roughly equivalent to missing an entire year of school," said Joseph A. Schwartz, lead author and a research assistant and doctoral candidate at Florida State University in Tallahassee. "Previous studies have suggested that complicated or repeated head injuries can result in diminished levels of information processing and language fluidity, which indicates that overall intelligence may be affected as well," Schwartz said.

The findings come from an analysis of data from the National Longitudinal Study of Adolescent Health, which was conducted in three waves between 1994 and 2002 and included nearly 15,000 young people who were between ages 12 and 21 in 1994. They were surveyed about a wide range of topics, including how many times they had been in a physical fight in the previous 12 months that caused any injury serious enough to require medical attention. Verbal IQ was also assessed.

7.2 percent of the overall sample experienced at least one serious injury due to fighting (10.2 percent for males and 4.5 percent for females) and each fighting related injury resulted in a loss of 1.89 IQ points. Young women who had been injured in a fight seemed to fare worse, dropping 3 IQ points.

However, since the study determined only that injuries had occurred and not what types of injuries occurred, it is not known whether head injuries created a more serious cognitive problem than injuries elsewhere to the body. "Another possibility is that a physical fight, even one that does not cause injury, may contribute to cognitive decline by causing physical stress," said Richard A. Lipton, professor at Albert Einstein College of Medicine of Yeshiva University in the Bronx and a spokesperson for the American Academy of Neurology. He noted that the magnitude of the injuries was also not explored since the survey only asked about injuries that required medical attention, which means that a minor injury counts the same as a severe concussion or unconsciousness.

Why girls showed a greater loss in cognitive function than boys is not known. There may be physiological differences between boys and girls that allow boys to withstand more severe physical damage than girls, noted Schwartz. The difference may also be due to a reporting bias, said Lipton, since boys may be more likely to remember and report a fight injury because fighting may be viewed as more acceptable for boys than it is for girls.

Source: Albert Einstein College of Medicine