Intergenerational influences of the cognitive and non-cognitive components of parental education on externalising and internalising difficulties in childhood and adolescence.

Educational attainment is associated with mental health across development. What drives this association remains unclear, as it may reflect both genetic transmission and nongenetic intergenerational processes, which may operate differently for the cognitive and non-cognitive components of educational attainment. Using polygenic scores as proxies for the cognitive and non-cognitive components of educational attainment, we examined their developmental associations with early markers of mental health, i.e. externalising and internalising behaviour. We analysed data from 3,223 mother-father-child trios from the UK Millennium Cohort Study, applying a genetically informed design to distinguish genetic transmission (direct inheritance) from indirect genetic effects (non-transmitted parental genetic associations). For externalising behaviour, cognitive and non-cognitive components showed a nominally significant developmental trend: genetic transmission increased from early childhood (age 3) to adolescence (age 14), while indirect genetic effects were evident in early childhood but less consistent at later ages. In contrast, genetic influences on internalising behaviour were relatively stable across development, with small and overlapping indirect genetic effects for cognitive and non-cognitive components in early childhood and modest, overlapping genetic transmission in adolescence. Our results underscore the importance of considering both cognitive and non-cognitive dimensions in a developmentally informed framework to fully understand the role of education-related traits in the intergenerational transmission of mental health.