Sept. 24, 1999 (Atlanta) -- Contrary to popular opinion and the experts' prevailing wisdom, disruptive boys generally do not grow up to be disruptive adolescents, according to the findings of a study published in the September/October issue of Child Development. But the researchers found that the boys who displayed physical aggression as children were more prone to violent behavior in their teens.
"We found that many boys who had behavioral problems when they started school became better adjusted as they grew older," says lead author Daniel Nagin, PhD, from Carnegie Mellon University in Pittsburgh. "Our findings suggests when you are focusing and concerned about later violent behavior, what seems to be very important is the presence of violent physical aggression during childhood years. Violence, particularly serious violence, is not the kind of thing that tends to emerge from nowhere -- it tends to be part of an ongoing pattern," Nagin tells WebMD.
In 1984, Nagin and his colleague Richard Tremblay, from the University of Montreal, began studying a group of more than 1,000 French-speaking, nonimmigrant white boys from 53 schools in low socioeconomic areas in Montreal. The boys were all in kindergarten at the time (around 6 years old). Their teachers were asked to rate them on physical aggression (kicks, bites, hits, fights, bullies), on opposition or defiant behavior (doesn't share; is inconsiderate, irritable, disobedient; blames others), and on hyperactivity (fidgets, squirms, can't sit still).
Their teachers rated the boys again at ages 10, 11, 12, 13, 14, and 15. Then, at ages 15, 16, and 17, the subjects themselves filled out questionnaires about delinquent and violent behavior. Additionally, their official juvenile records were opened and reviewed after they turned 18.
"Boys who display high levels of hyperactivity in their childhood, but not of physical aggression, don't seem to be at greater risk for being violent later on in life. I think this is important, particularly for parents, because there is a general fear out there that hyperactivity is associated with bad ends of all sorts," Nagin says.
Nagin says this misconception may have arisen because most of the studies that examined disruptive behavior in children tended to lump together different types of behavior, like hyperactivity and physical and verbal aggression. Because of these broadly defined categories, many studies concluded that any troublesome behavior during childhood predicts violence in adolescence and adulthood. But as these researchers point out, "this does not mean that these other problem behaviors are equivalently predictive of physical violence later in life."
"Still another important finding of our study was that these things that we called trajectories -- how these behaviors play out over time -- were all stable or declining," says Nagin. "The implication of that is that origins of these behaviors are starting some time before the beginning of study, which in our case was age 6. So one of our conclusions was that it is important to look back even further in time to begin to understand the developmental origins of this behavior."
The study was funded in part by grants from the Molson Foundation and the National Consortium on Violence Research.