Moreover, medications that have typically been useful to some extent in relieving cognitive symptoms of dementia, including acetylcholinesterase blockers (donepezil, rivastigmine, galantamine) and N-methyl-D-aspartic acid antagonists (memantine), have had no clinically or statistically significant effects on cognition in adults with ADHD (Wilens et al., 2005; Biederman et al., 2006b), further suggesting that the underlying pathological etiologies of ADHD and dementia are distinct. This evidence concerns the gene ACHE and attention deficit-hyperactivity disorder.