Does a parent's depression drag down a kid's grades?

Researchers tracked about 9,000 families in the Norwegian Mother, Father, and Child Study and compared cousins to strip out shared family background. Small links between parents' psychiatric symptoms and children's 5th-grade test scores disappeared once cousins were compared.

It is a familiar assumption that a parent's anxiety, depression, ADHD, eating disorder, or drinking problem will show up in their child's report card. This study asked whether that link is actually causal. Using roughly 9,000 families from the large Norwegian Mother, Father, and Child Study, researchers had parents report their own symptoms during pregnancy and again during the child's childhood. The children then took Norway's nationally standardized 5th-grade tests in math, reading comprehension, and English at about age 10. The clever part is the design: instead of comparing unrelated families, the team compared children who are cousins, so that everything siblings-turned-parents share (genes, upbringing, neighborhood, social class) is held constant. In the ordinary analysis, more parental symptoms went with slightly lower reading and math scores, but the effects were tiny, with standardized betas between -0.060 and -0.013. In the cousin comparison, those associations were no longer statistically significant. The authors read this as evidence that parental symptoms do not directly move a child's achievement much on their own. One honest limitation: the families who could be included in the cousin analysis differed from the full sample, so the results may not generalize cleanly to all families, and the design cannot rule out very small effects.