Nightmares are scary dreams that awaken children and make them afraid to go back to sleep. Nightmares may happen for no known reason, but sometimes occur when your child has seen or heard things that upset him/her. These can be things that actually happen or are make-believe.
Occasional bad dreams are normal at all ages after about 6 months of age. Nightmares often relate to developmental stages of a child: toddlers may dream about separation from their parents; preschoolers may dream about monsters or the dark; school-aged children may dream about death or real dangers. Nightmares usually happen during the last third of sleep, during REM (dream time) sleep.