Genetic correlation of the ADHD GWAS with the 23andMe and EAGLE/QIMR results was computed using LD score regression37 with pre-computed European ancestry LD scores following the same procedure as described above for other genetic correlation analyses. Genetic correlation could not be computed for deCODE since results were only available for top loci from the ADHD GWAS. To further explore the moderate genetic correlation between the 23andMe results and the ADHD GWAS we also evaluated the genetic correlation between 23andMe and traits from LD Hub (see URLs)42. To evaluate the magnitude of the observed differences in rg we consider both the absolute difference (i.e. rg,ADHD−rg,23andMe) and the test of an approximate Z score for this difference (Supplementary Information): Z=rg,ADHD−rg,23andMeSEADHD2+SE23andMe2
