While these results provide tentative evidence for the utility of the age-specific PGS in adulthood, the observed effect of the age-specific PGS was relatively small. Nominal differences in BIC also depart from this pattern, instead suggesting that the model with just covariates provided the best fit to the data. Neither PGS demonstrated significant effects when modeled together and the age-specific PGS did not improve model fit significantly above a model that included the common factor PGS when tested via likelihood-ratio test. Larger samples may be required to more clearly delineate the effects of the common factor PGS and the age-specific PGS. The results of the power simulation suggest that future developmentally-informative GWAS that apply the approach described in the current study may need large sample sizes, in excess of 500,000, to detect reliable SNP effects.
