More Siblings May Come With Poorer Mental Health

More family, more problems? A new study suggests this may be the case for teens crowded by siblings. The Guardian breaks down the findings of lead author Doug Downey, a professor of sociology at Ohio State who analyzed the mental health of middle schoolers in China and the US. The students, averaging 14 in age, have been part of a long-term study since kindergarten. They answered questions about their mental health that varied by country, and those with larger families had poorer results. "Our results couldn't have been easily predicted before we did the study," Downey said, per Cleveland.com. "Other studies have shown that having more siblings is associated with some positive effects, so our results were not a given."

A few specifics popped out for the families with more siblings. In China, the teens with no siblings (more common due to the one-child policy) had the best mental health, while in the US, teens with no or one sibling had similar results. The biggest effects on mental health were seen from families with many children born less than a year apart. Having many brothers and sisters, older siblings, and siblings closely spaced in age all showed higher negative impacts on mental health. Downey says that when siblings are closer in age, it becomes a matter of resource dilution.

"If you think of parental resources like a pie, one child means that they get all the pie," he said. "But when you add more siblings, each child gets fewer resources and [less] attention from the parents, and that may have an impact on their mental health." But other factors, like socioeconomic status and the quality of sibling relationships, need to be looked at more closely. Previous research contradicts some of the negative aspects of these findings—a 2016 study out of Norway found that children in larger families had better mental health, and Downey's previous research associated big families with lower divorce rates down the line. He hopes to build on this research, as lower fertility rates in both countries make the topic "an increasingly important social issue." (Magicians rank higher in mental health than other performers.)