PLOD1 and attention deficit-hyperactivity disorder: Finally, increased RH relative to LH contribution may be consistent with common ADHD characteristics, such as: increased leftward motor preference (69, 70), which has been linked to greater RH contribution to language (71, 72); being male (73), as males tend to exhibit better visual-spatial and poorer linguistic abilities compared to females (74, 75), and dysregulated dopamine and noradrenergic function (76), as these systems appear to exhibit a degree of LH and RH specialization respectively (77).