We next used Genomic SEM10 to conduct a GWAS on the shared genetic liability EXT (Figure 2 and Extended Data Fig. 2). This analysis estimated single-nucleotide polymorphism (SNP) associations directly with EXT, with an effective sample size of N = 1,492,085 individuals (Supplementary Information section 3.4). These analyses are different in their approach and substantially increase sample size, statistical power, and the range of findings compared to previous work (Supplementary Information section 2.2.1). After applying conditional and joint multiple-SNP analysis (COJO) on a set of near-independent, genome-wide significant (two-sided P < 5×10−8) lead SNPs23, we identified 579 conditionally and jointly associated “EXT SNPs” (Supplementary Tables 9–9B), meaning they were significantly associated with EXT even after statistically adjusting for each other and other lead SNPs. Of the 579 EXT SNPs and their correlates within linkage disequilibrium (LD) regions (r2 > 0.1), 121 (21%) were new loci, not previously associated with any of the seven externalizing behaviors/disorders that went into the Genomic SEM model, and 41 (7%) can be classified as entirely novel, as they have not been reported previously for any
