In this study we demonstrate, not for the first time [22,40,41], the ADHD-like phenotype of DAT-KO rats: in the Hebb–Williams maze, compared to WT, DAT-KO rats made more errors, took a longer time and traveled a longer distance to reach the goal box and exhibited perseverative returns. This evidence concerns the gene SLC6A3 and attention deficit-hyperactivity disorder.