Finally, advances and obstacles in the symptomatic and causal treatment of narcolepsy are reviewed. The limitations of current diagnostic criteria for narcolepsy are discussed, and a possible new classification system incorporating the borderland conditions is presented. Data supporting the view of NT1 as a hypothalamic disorder affecting not only sleep–wake but also motor, psychiatric, emotional, cognitive, metabolic and autonomic functions are presented, along with uncertainties concerning the ‘narcoleptic borderland’, including narcolepsy type 2 (NT2). This Review focuses on our current understanding of how genetic, environmental and immune-related factors contribute to a prominent (but not isolated) orexin signalling deficiency in patients with NT1. Symptomatic treatment with stimulant and anticataplectic drugs is usually efficacious. Diagnosis is based on these clinical features and supported by biomarkers: evidence of rapid eye movement sleep periods soon after sleep onset cerebrospinal fluid orexin deficiency and positivity for HLA-DQB1*06:02. Narcolepsy type 1 (NT1) is characterized by excessive daytime sleepiness and cataplexy, accompanied by sleep–wake symptoms, such as hallucinations, sleep paralysis and disturbed sleep. Narcolepsy is a rare brain disorder that reflects a selective loss or dysfunction of orexin (also known as hypocretin) neurons of the lateral hypothalamus.

Narcolepsy with cataplexy treatment