Night terrors: Sudden fear during deep sleep explained by expert

Night terrors, or sleep terrors, involve sudden arousal with intense fear during stages 3 or 4 of non-REM sleep, typically in the second half of the night. Dr Sarthak Dave says that they're marked by a scream and extreme anxiety, the person is partially awake, unresponsive, and confused if woken. Night terrors lack detailed images or memory of the dream.