This relates to children as well as adults. The general adult themes involve fears, such as being chased or attacked. The person experiencing the nightmare often has physical sensations. There is a theme suggested here where what we dream is related to our surrounding environment and what events are occurring in our lives. In particular, nightmares occur following significant real events in life that are psychologically painful, such as a death in the family or being the victim of an assault.
Nightmares are also involved with physical illness, which includes high fever.
It also suggests that we can sense physically what is happening during this parasomnia sleep. The lesser intensity of the REM anxiety dream may be at least partially explained by the fact that during REM the physiological activation provides a buffer which prevents extreme terror. This physical movement also helps the body awaken to avoid the nightmare altogether and awaken the dreamer. The nightmare provokes a retaliatory response, both in dream content and in actual physical movement. The resulting body movement is usually sufficient to cause an awakening.