intensive nature of neuroimaging limit their clinical utility. Further, these small effects combined with multiple testing burden may have contributed to false negatives; as such null effects should not be interpreted to suggest that an association observed in adults may solely reflect neurotoxicity. Third, as the discovery GWAS were of individuals of predominantly European descent, we restricted our ABCD sample to children of similar ancestral background. Our analyses in the smaller African-ancestry sample (N = 898) of ABCD revealed no significant results (Supplemental Table 3), likely due to low power of the discovery GWAS of matched ancestry (N = 62,447 vs. 352,365 for the European-ancestry GWAS) as well as the smaller ABCD sample. This highlights the need for more and larger non-European discovery GWAS.
