Narcolepsy and other causes of excessive daytime sleepiness.

Narcolepsy is a chronic disorder characterized by excessive daytime sleepiness, cataplexy, and other auxiliary symptoms. An interview can ascertain specific symptomatology, whereas a polysomnogram can reveal distinct clinical features. The clinical and laboratory evaluation together enable an accurate diagnosis of narcolepsy. This diagnosis includes a wide spectrum of symptom combinations. Treatment of narcolepsy should include the empathic guidance of a sleep clinician, an emphasis on sleep hygiene, and in many cases pharmacotherapy.