MAOB and attention deficit-hyperactivity disorder: Another study has shown an increase in 3-ortho-methyldopa (the metabolite resulting from the degradation of dopamine by monoamine oxidase B), suggesting a possible hyperdopaminergic mechanism, which contradicts the therapeutic effects mentioned earlier and once again demonstrates the extent of the progress to be made in understanding the involvement of the dopaminergic system in RLS [56], and consequently its link with ADHD.