2010, 2012; Acosta et al. 2011; Martinez et al. 2011; Ribases et al. 2011; Jain et al. 2012). Furthermore, ADGRL3 susceptibility variants interact with haplotype variants harbored at chromosome 11q22 in the region of NCAM1, TTC12, ANKK1, and DRD2 genes (Jain et al. 2012). It is clear now that the association between ADHD and ADGRL3 variants identifies a subtype of the condition characterized by the presence of severe externalizing symptoms and consequently a complex prognosis of persistence and graveness. Here, DRD2 is linked to attention deficit-hyperactivity disorder.