Nightmares are bad dreams, sometimes alive, that often make you wake up.
Once awakened from a nightmare, you may have trouble getting back to sleep, either due to additional anxiety or as part of a larger, broken sleep problem.
The word nightmare comes from the ancient English folklore " Mare ", a demon that torments its victims with bad dreams.
Nightmares are common, especially in young children, although it also occurs in adults. They are completely normal and can appear and disappear in time. Nightmares only become a problem when they are frequent. The official medical term for frequent recurring nightmares is the nightmarish disorder.