What defines a night terror?

A night terror is characterized by sudden awakenings from non-REM sleep, typically occurring during the first few hours of the night. These episodes are often marked by intense fear or panic, along with physical symptoms such as screaming, thrashing, or rapid heart rate. Unlike nightmares, which occur during REM sleep and can be remembered upon waking, night terrors are usually not recalled clearly, as the individual is often deeply asleep during the episode.

This distinction is important in understanding the nature of sleep disturbances. In this case, the occurrence of night terrors is specifically linked to non-REM sleep phases, particularly slow-wave sleep, which is a state of deep sleep. As a result, the correct answer conveys the essential aspect of night terrors that sets them apart from other sleep phenomena, such as nightmares or sleep disorders associated with REM sleep.