Epidemiology of narcolepsy

This chapter provides an overview of the epidemiology of narcolepsy. Narcolepsy is characterized by excessive sleepiness with episodic weakness often triggered by strong emotions. Due to difficulty in diagnoses, misdiagnosis, and delayed diagnosis, measurement of prevalence rates in population-based samples is complicated. However, the most intensively screened population-based studies suggest that prevalence rates for narcolepsy with cataplexy range between 25 per 100,000 and 50 per 100,000 people. Some studies show that men are more likely than women to have narcolepsy, but it is hard to tell with such a rare disorder and frequent misdiagnosis. Other correlates of narcolepsy include low hypocretin levels, presence of the HLA DQB1 602 gene, obesity, and other sleep disorders. Symptoms of narcolepsy commonly begin in the second decade of life and last a lifetime. Treatment of the disorder usually requires medications and behavioral modification.