ADK and attention deficit-hyperactivity disorder: Although not achieving significance after multiple comparison correction, CpG sites in ADHD-related genes were found among the top ten signals of the EWAS, including CREM, which has been previously associated with impulsivity, hyperactivity, anxiety-like behavior, circadian rhythmicity and drug addiction60–62, ADK, whose deficiency may result in altered dopaminergic function, attentional impairment, and learning impairments63,64, or LAT, whose genetic variation has been associated with educational attainment65.