The correct answer is narcolepsy
Narcolepsy is a sleep disorder characterized by excessive sleepiness during the day and frequent attacks of sleep, even when the person slept well at night. These attacks tend to occur suddenly and at any time of the day - even in unusual situations, such as at medical appointments, driving or in a conversation between friends.
Contrary to what many believe, narcolepsy is not related to depression, seizure disorders, fainting, laziness or the simple lack of sleep at night. This is a chronic condition, for which there is no cure, and which can seriously affect the quality of life of those who have it. However, it is perfectly treatable and its main symptom - excessive sleep during the day - can be controlled through medications and some lifestyle changes.