Everyone has bad dreams at times. If they happen once in a while, it is usually not anything to worry about.
Some people dream a different dream every time they have a nightmare.
Some people may have the same nightmare over and over again. People with a nightmare disorder have a severe problem with nightmares. Nightmares happen frequently in childhood, especially between the ages of three and six. Most children outgrow them. In a few people, they continue into adulthood.