· A nightmare, also called a bad dream, is an unpleasant dream that can cause a strong emotional response from the mind, typically fear but also despair , anxiety and great sadness . · They often set heart pounding from fear. · The dream may contain situations of discomfort, psychological or physical terror or panic. Sufferers often awaken in a state of distress and may be unable to return to sleep for a short period of time. · Frequent occurrence of nightmares, however, 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," which is a term defined more sp...