Excessive daytime sleepinessis characterized by persistent sleepiness, and often a general lack of energy, even after apparently adequate night time sleep. Sudden involuntary sleep onset are common complications EDS is a symptom of one of the two forms of the sleep disorder,the other being prolonged nighttime sleep. Some persons with EDS are compelled to nap repeatedly during the day; fighting off increasingly strong urges to sleep during inappropriate times such as while driving, while at work, during a meal, or in conversations. As the compulsion to sleep intensifies, the ability to complete tasks sharply diminishes, often mimicking the appearance of intoxication.