DRD4 and attention deficit-hyperactivity disorder: Recent meta‐analyses have suggested that the DRD4 7‐repeat (7R) allele is associated with ADHD (Faraone & Mick, 2010; Li, Sham, Owen, & He, 2006); however, Asian populations, including Koreans, rarely exhibit this allele (Tomitaka et al., 1999).