Definition of Night terror:

Night terrors are a sleep disorder in which a person quickly awakens from sleep in a terrified state.

Causes, incidence, and risk factors:

The normal sleep cycle involves distinct stages, from light drowsiness to deep sleep. During rapid eye movement (REM) sleep, the eyes move quickly and vivid dreaming is most common. Each night there are several cycles of non-REM and REM sleep.

Night terrors (sleep terrors) occur during stage 3 and stage 4 sleep (deep sleep). The cause is unknown but night terrors are often triggered by fever, lack of sleep, or periods of emotional tension, stress, or conflict.

Night terrors are like nightmares, except that nightmares usually occur during REM sleep and include unpleasant or frightening dreams. Nightmares are most common in the early morning.

Night terrors usually happen in the first half of the night. The child often screams, and will usually not remember the details of the scare. You may be unable to talk to a child who is having a night terror. In contrast, nightmares are normal on occasion, especially after someone watches frightening movies/TV shows or has an emotional experience. A person may remember the details of a dream upon awakening, and will not be disoriented after the episode.

Night terrors are most common in preadolescent boys, although they also can occur in girls and in adults. They are fairly common in children 3 - 5 years old, and much less common after that. Night terrors may run in families. They can occur in adults, especially with emotional tension and/or the use of alcohol.