A nightmare is a dream occurring during rapid eye movement (REM) sleep that results in feelings of strong terror, fear, distress or extreme anxiety. This phenomenon tends to occur in the latter part of the night and oftentimes awakens the sleeper, who is likely to recall the content of the dream.
Most nightmares may be a normal reaction to stress, and some clinicians believe they aid people in working through traumatic events. Frequent occurrence of nightmares becomes a disorder when it impairs social, occupational and other important areas of functioning. At this point, it may be referred to as Nightmare Disorder (formerly Dream Anxiety Disorder) or "repeated nightmares."
"Repeated nightmares" is defined more specifically as a series of nightmares with a recurring theme. Nightmares usually begin in childhood before age 10 and are considered normal unless they significantly interfere with sleep, development or psychosocial development. They tend to be more common in girls than boys, and they may continue into adulthood. Adult nightmares are often associated with outside stressors or exist alongside another mental disorder. Nightmares might be associated with anxiety and trauma.
A closer look at dreaming might help in understanding nightmares.
