Narcolepsy

Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep-wake cycles. People with narcolepsy experience "excessive daytime sleepiness and intermittent, uncontrollable episodes of falling asleep during the daytime." Sudden sleep attacks occur during any type of activity and at any time of the day.

Autoimmune disease
Researchers at Stanford University School of Medicine have believed for some time that narcolepsy is an autoimmune disease. The National Organization for Rare Disorders (NORD) also states that there is increasing evidence that it is an autoimmune disorder. NORD notes that "the immune system destroys certain brain cells that produce a peptide called hypocretin. Hypocretin impacts on many brain functions, but the details of its actions are not yet understood." In March 2019, researchers from the University of Copenhagen reported that they discovered autoreactive (produced by an organism and acting against its own cells or tissues)   CD8 T cells in persons suffering from narcolepsy.