Some of the most promising H3R ligands such as, e.g., GSK239512, MK-0249, ABT-288, SAR110894 or pitolisant entered clinical trials for the potential treatment of AD, dementia, ADHD, narcolepsy, multiple sclerosis, obesity, or schizophrenia [10, 11]. The gene discussed is HRH3; the disease is Alzheimer disease.