Nightmares and the Mood Regulatory Functions of Sleep

Nightmares are frightening dreams that most often occur during rapid eye movement (REM) sleep. Up to 50% of children between 3 and 6 years of age and 20% between 6 and 12 years of age experience frequent nightmares, and 2-6% of the American adult population experiences nightmares at least once a week. Nightmares typically appear during one of the late REM episodes that occur during the early morning period between 4 and 7 a.m., and these episodes are associated with heightened activation levels in the amygdala. Nightmare content typically involves extreme anxiety, fear, or terror and simulates physical threat to the dreamer by animals, strangers, or supernatural beings or monsters. Recurrent nightmares occur frequently in recurrent nightmare disorder, posttraumatic stress disorder, REM behavior disorder, and other neuropsychiatric syndromes. Nightmares may be due, in part, to dysfunction in the normal mood regulatory functions of REM sleep.