Narcolepsy is a sleep disorder that is characterized by uncontrollable attacks of deep sleep. Symptoms of narcolepsy include excessive daytime sleepiness, sudden loss of voluntary muscle tone, vivid hallucinations upon falling asleep or upon awakening, and brief total paralysis at the beginning or end of sleep. Treatment options include drug therapies, scheduled naps, maintaining a sleep schedule, avoiding stimulants before bed, and yohimbe.