Narcolepsy is a nervous system disorder whose exact cause in unknown. We do known, however, that it is rooted in genetics and passed along from parents to their offspring. In some patients, narcolepsy is linked to decreased amounts of the protein hypocretin. In other, it may be caused by a deficiency in the production of the neuropeptide orexin by the hypothalamus. It may also be an autoimmune disorder, a terms that refers to conditions caused by the body’s immune system mistakenly attacking healthy tissue.