Scientists from the Netherlands have found that genetic variants associated with higher educational attainment may be linked to fewer behavioral and emotional problems in children and adolescents. Specifically, these are attention problems and physical complaints caused by stress. The work was published in the journal Behavior Genetics.
The study used a polygenic index (PGI), a mathematical measure that sums up many tiny associations in DNA identified in large population studies. Such an index does not measure an innate trait but reflects the statistical association of genes with a trait, for example the number of years of schooling.
The authors analyzed data from 4,008 children and adolescents aged 4 to 17 from the Lifelines study (northern Netherlands). A total of 7,787 observations were collected. The participants were of European origin, and in most cases the genome of at least one parent was statistically reconstructed rather than measured directly.
Behavioral difficulties were assessed using standard questionnaires. Parents completed 4,611 questionnaires, and adolescents aged 13-17 completed 3,176 self-report questionnaires. The scientists split the overall polygenic index for education into two parts: cognitive (linked to scores on thinking tests) and non-cognitive (everything else). They then tested how these parts were related to eight types of behavior.
It turned out that children with a higher overall education index had fewer of some problems, but a consistent link appeared only for a few areas. Moreover, it ran mainly through the cognitive component. In particular, higher values of the cognitive part were associated with fewer attention problems according to parent ratings and with fewer physical complaints about stress according to adolescent self-reports. The link with anxiety and depressive symptoms according to parent ratings was less consistent.
The non-cognitive part showed weak and unstable associations that did not hold up to statistical testing. However, as lead author Lyudia Alayaaskyo noted, this does not mean that the non-cognitive pathway is unimportant: the study may simply have lacked the power to detect weak effects.
The parents' own polygenic indices were not significant predictors of children's behavior in the main models. This suggests that the link is unlikely to be explained solely by the home environment created by the parents' genes. But the authors emphasize that even direct associations are not purely biological, since they may include other people's reactions to the child's characteristics.
When boys and girls were analyzed separately, notable differences emerged. In girls, the cognitive part consistently predicted lower levels of anxiety and depressive symptoms, unusual or obsessive thoughts, attention problems and aggression according to parent ratings. In girls' self-reports, the overall index was associated with fewer physical complaints and internal problems, while the cognitive part was associated only with physical complaints. In boys, the initial associations disappeared after accounting for parental indices.
The authors suggest that cognitive skills and behavioral regulation may share a common neurocognitive basis, such as executive functions (working memory, self-control). But since these functions were not measured directly, the explanation remains hypothetical.
The scientists warn that polygenic indices are statistical summaries, not a verdict. They also reflect the social conditions in which genetic differences manifest themselves. In addition, the sample is limited to people of European origin from one country, which reduces generalizability. Statistical power for detecting very weak effects is also limited.