Genetics of educational attainment and social problem behaviors: Robust estimates of direct genetic effects

This study examines the genetic underpinnings of (problematic) social behaviors by
leveraging a within-family trio design using data from the Lifelines cohort (N=3,090-4,510).
Socio-emotional development is key to understanding long-term educational, occupational,
and mental health outcomes. Yet, their genetic foundations are not fully understood. We estimate direct genetic effects of educational attainment (EA)-related polygenic indices (PGIs),
as a whole and decomposed into cognitive (Cog) and non-cognitive (NonCog) components,
on a comprehensive set of internalizing and externalizing behaviors assessed via self- and
parental-reported Achenbach System of Empirically Based Assessment (ASEBA) measures.
Our findings reveal that higher EA-related PGIs, particularly their cognitive component,
are robustly associated with lower levels of attention problems, rule-breaking, and somatic
complaints. These effects persist after adjusting for parental genetics, supporting a causal
interpretation. We find notable sex differences, with stronger associations in girls, especially
for internalizing traits, and observe modest (although insignificant) differences between selfand parent-reported outcomes. No evidence was found for indirect genetic effects of parental
PGIs. Our findings contribute novel evidence that cognitive genetics influence behavioral
development and highlight the value of family-based genetic designs for uncovering the complex interplay of genes and environment in socio-emotional functioning.
Keywords
Social behavioral traits, cognitive/non-cognitive traits, educational attainment, polygenic indices, within-family trio design, sex.