What a Nightmare

Thank goodness it's only a dream.

Posted May 30, 2011

Joey was a young man I met at the Boston VA who had been deployed to Iraq and suffered several near misses in explosions that took out at least one other member of his platoon. Joey was an educated guy, older relative to the age of his comrades and much more educated than his friends. When he returned from Iraq he slowly began to develop repetitive nightmares that left him drained and exhausted and on edge during the day. In the nightmare, he heard nothing but could sense an enormous, ear shattering blast just behind as well as all kinds of flying glass, and debris. In the debris he thought there might be pieces of human flesh.

On memorial day we remember vets who have served in foreign wars. Many of those vets come home from the warzone suffering repetitive nightmares. Sometimes these repetitive nightmares turn into a full blown post-traumatic stress disorder (PTSD). One of the core symptoms of PTSD is the presence of distressing nightmares.

Nightmares are one of the most unpleasant aspects of dreaming.  Nightmares are dreams that are terrifying to the dreamer and sometimes so much so that they awaken the dreamer. When we awake from a terrifying dream and say to ourselves 'thank god it was only a dream!'... then we know we have had a nightmare. Two to five percent of the adult population report nightmares 'often or always' and 8% to 30% of the adult population have a nightmare at least once a month. About 4% of parents report that their preschool children have frequent nightmares. Nightmares increase in frequency in the pre-adolescent and adolescent years -especially for girls. Women on average report more frequent and more intense nightmares then do men.

Nightmares are also associated with trauma. If you experience some kind of traumatic event the chances that you will experience a nightmare soon after the traumatic increase significantly.In vets exposed to war-related blast injuries or other forms of trauma PTSD may develop.  Ernest Hartmann has suggested that nightmares point to an emotional integration function for dreams more generally. Ross and Levin have suggested a similar affect regulation theory of dreaming and its breakdown with nightmares.  These theories suggest that when the emotion to be integrated into long term memory is too intense the integrative function of dreaming can breakdown and repetitive nightmares are the result.

Nightmares most often occur in REM episodes that occur toward the early morning hours. This fact suggests that something about the biology of REM facilitates the nightmare. Interestingly in PTSD nightmares may occur both within a REM episode and without a REM episode (i.e. as part fo NREM). To me the most likely candidate neuroanatomical locus for nightmares is the amygdala, that is over-activation of particular portions of the amygdala. Neuroimaging studies of the dreaming brain have demonstrated that the amygdala is intensely activated during REM. Independent, non-sleep-related studies of the amygdala have established it as a processing center for fear, aggression and other negative emotions. It would not be surprising if over-activation of the amygdala during REM can create intense fear-responses in the individual. 

Whatever the physiologic causes of nightmares people have discovered, and scientists such as Barry Krakow have confirmed that taking a scary image from the nightmare and then performing exercises that de-sensitize oneself to the image seem to help with the distress that occurs with nightmares.

Reference: McNamara, P. (2008). Nightmares: The science and solution of those frightening visions during sleep. Westport,         CT: Praeger Perspectives.