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My wife and I recently packed our 2-year-old twins into their car seats and moved them halfway across the country to a new home in Minnesota. During the five or so days we spent on the road with them, we had ample opportunity to reflect on what sorts of terrible harms we were inflicting on their fragile little toddler brains.

Did they understand what was going on? Would they like the new place when they got there? Were we destroying their chances of ever getting into Harvard by letting them watch eight hours of garbage cartoons in the back seat of a Honda CR-V, day in, day out?

As it turns out, a study recently published in the American Journal of Preventive Medicine has some answers to those questions. British researcher Roger Webb and his colleagues took advantage of an amazingly complete data set — containing records on literally every single person born in Denmark between 1971 and 1997 — to investigate how moving in childhood affected outcomes later in life.

The focused on a number of negative outcomes including suicide attempts, criminality, psychiatric disorders, drug abuse, and unnatural mortality. Moving during childhood was linked to increased incidence of all these negative outcomes later in life. Moving multiple times in a single year made long-term harms even more likely.

And the group of youngsters most likely to feel the ill effects of moving are kids in early adolescence, between 12 and 14. A child who goes through a residential move at age 14 has double the risk of suicide by middle age. Her risks of engaging in violent crime of abusing drugs more than double. And these risk ratios hold true even after controlling for parents' income and psychiatric history.


Crucially, this study looked only at moves across Danish municipal boundaries — far enough that it would typically require a child to change schools. The researchers argue that fact goes a long way toward explaining the results.

"Relocated adolescents often face a double stress of adapting to an alien environment, a new school, and building new friendships and social networks, while simultaneously coping with the fundamental biological and developmental transitions that their peers also experience," Webb and his colleagues write.

There are, of course, different reasons that people move. Moves done in an orderly fashion in early childhood —  say, for a parent's new job, or in order to trade up to a nicer home — may have a different impact on children's lives than a chaotic cross-town move due to an eviction.

Unfortunately, the data from Denmark doesn't include information on the reasons behind the moves. But Webb and his colleagues were able to control for things — such as parents' socioeconomic status — that may predict one type of move or another.

They found that rich kids experienced heightened risks from moving just as much as poor kids, particularly in adolescence. "Residential mobility among older children, even in more-affluent households, may occur in parallel with severe family stressors such as parental separation," they hypothesize.

Webb's somewhat disturbing conclusion? "Mobility may be intrinsically harmful."

It's important, however, to keep these findings in perspective. The study mostly looks at moving in isolation. Other factors that change with a move may have even greater impacts on children's risk of developing later social problems.

For instance, there's a robust body of research on how living in a bad neighborhood has drastically negative consequences for children in later in life. The benefits of moving from a bad neighborhood to a good one, even during early adolescence, probably far outweigh the risks associated with the move itself. Similar for moves that involve, say, a much higher-paying job.

In the end, the study adds quantitative rigor to what many of us had already suspected: Switching homes can be a highly disruptive experience for a child, particularly one navigating the complications of the early teenage years.

For the time being, my 2-year-olds seem no worse for the wear. In the end, our own move seemed to take its greatest toll on our beagle-basset mix dog, who by the fourth day of the trip refused to leave the hotel room and had to be carried out to the car.

Webb's study did not look at the impact of moving on pets, however.

From eating your vegetables to being kind to others, students at Our Lady of Mercy School in Maryland share the best advice from mom. (Jorge Ribas/The Washington Post)