These results are consistent with previous studies that have reported associations between being a carrier of 7R and impairment on executive function tasks in healthy children [50], adults [54] and in children with ADHD [50]–[52]; they also support the findings of those authors who have reported better performance among subjects with the DRD4 long (6–8) repeats compared to the DRD4 short (2–5) repeats [53]. This evidence concerns the gene DRD4 and attention deficit-hyperactivity disorder.