People who stay awake all night, especially for several nights in a row, suffer from sleep deprivation. Not getting enough rest disrupts your life, and sleep deprivation can make some health conditions worse.
Everyone needs a certain amount of sleep in order for their brains and bodies to function. When we don't get enough, we suffer from sleep deprivation. Being deprived of a good night's snooze can have various causes, including eating a lot of chocolate before bed, too much stress, or staying up all night studying (or watching videos on your phone). If it's deliberately imposed on someone, sleep deprivation is considered a form of torture that affects physical and mental health.