Narcolepsy in adolescents.

Narcolepsy is a disorder of children and adolescence, but until recently it was often not identified until adulthood, with a reported time from onset to diagnosis of about a decade. This disorder affects approximately 0.05% of the population and starts in childhood and adolescence about half of the time. With narcolepsy, the boundaries between wake, sleep, and dreams are blurred. The cardinal features of narcolepsy-cataplexy are daytime somnolence, cataplexy (sometimes occurring long after onset of sleepiness), sleep paralysis, and hypnagogic hallucinations. Weight gain, disturbed nocturnal sleep, and social/school functional changes are common; reactive substance use to maintain wakefulness during the day may also be seen. Males and females are equally affected. It is classically associated with HLA DQB1*0602, the most specific genetic marker for narcolepsy across all ethnic groups. CSF hypocretin has recently been found to be depleted in this disorder, and late-breaking data support that the disease is caused by autoimmune destruction of hypocretin-producing neurons in the hypothalamus. There is no known cure for narcolepsy. Therapies include behavioral/ scheduling modification, medications to combat daytime sleepiness and cataplexy, and treatment of concomitant disorders leading to daytime sleepiness. The differential diagnosis for this disorder should include other disorders of excessive daytime sleepiness with a proclivity toward onset in adolescence, such as delayed sleep phase syndrome, obstructive sleep apnea, and insufficient sleep time; substance use; and less commonly neurologic disorders such as Klein Levin syndrome, Prader-Willi syndrome, and others. Immunomodulator therapy and hypocretin replacement are proposed therapies that hold promise for the future.