In addition, sleep-related eating disorder (SRED), a nonREM sleep parasomnia characterized by an interruption of overnight fasting with episodes of sleep feeding [49], is very frequent in narcolepsy type 1 (in which there is orexin deficiency), but not in idiopathic hypersomnia (in CSF orexin levels are within the normal limits) [50]. This evidence concerns the gene HCRT and idiopathic hypersomnia.