Orexins were first shown to be implicated in narcolepsy, insomnia [15,16,17,18,19,20,21] and stress responses [22,23,24,25], but it is worth mentioning that orexins have also been described to play major roles in other CNS disorders, comprising both neuropsychologic and neurodegenerative diseases. This evidence concerns the gene HCRT and central nervous system disorder.