AATK and attention deficit-hyperactivity disorder: The hyperactivity of KO mice was suppressed by methylphenidate (MPD) (Fig. 6E, means ± SEM, n = 14 for both WT and LMTK1 KO mice, ****p<0.0001 for injection, two-way repeated-measures ANOVA, ns, not significant), a psychostimulant drug that is commonly used to treat hyperactivity and inattention in children diagnosed with attention deficit/hyperactivity disorder (ADHD)25.