Methylphenidate, which is widely used for treatment of attention deficit hyperactivity disorder and which acts by blocking the dopamine and norepinephrine transporters, was administered to a single NPH patient (20 mg) in a double blind cross-over trial after she had been shunted; the drug as associated with improved cognitive performance and reduced apathy [264]. Here, SLC6A2 is linked to attention deficit-hyperactivity disorder.