Night terrors also known as a sleep terror or pavor nocturnus, is a parasomnia disorder, causing feelings of terror or dread, and typically occurring in the first few hours of sleep during stage 3 or 4 non-rapid eye movement NREM sleep.  They should not be confused with nightmares, with are a normal patholoogy of sleep.

However, they can also occur during daytime naps.

In Paternity, the patient, Dan suffers a night terror when he imagines Gregory House entering his room and cutting off his toes. In reality, Robert Chase confirms that Dan's experiencing night terrors.

Night terror at Wikipedia

Community content is available under CC-BY-SA unless otherwise noted.