and bipolar disorder36, which are among the most genetically correlated mental disorders50. Notably, for both MDD and ASD, around 75% of the variants shared with ADHD demonstrated concordant direction of association. The large sharing of variants influencing ADHD and other psychiatric disorders, when assessing both concordant and discordant allelic directions, suggests that the disorders are even more intermingled with respect to their common genetic architecture than previously thought based on their overall genetic correlations36,50. For common variants, the developmental trajectory towards ADHD might therefore be influenced by variants involved in several psychiatric disorders, but with disorder-specific allelic directions and effect sizes rather than actual ADHD-specific loci.
