Type 1 narcolepsy is characterized by the presence of cataplexy and loss of orexin (hypocretin) neurons that activate histaminergic neuron, which control wakefulness [66], whereas type 2 narcolepsy is characterized by the absence of cataplexy and normal cerebrospinal fluid hypocretin levels. Here, HCRT is linked to narcolepsy without cataplexy.