A nightmare is an unpleasant dream. Nightmares cause a strong unpleasant emotional response from the sleeper, typically fear or horror. The dream may contain a situation of extreme danger, or sensations of pain, bad events, falling, drowning, being raped, becoming disabled, losing loved ones, encountering unpleasant creatures or beings, being murdered, caught, attacked, eaten, squashed, stuck or burned, becoming diseased, frozen, trapped, decrepit, or otherwise facing death. Such dreams can be related to physical causes such as a high fever or being face-down on a pillow during sleep, or psychological ones such as psychological trauma or stress in the sleeper's life, or can have no apparent cause. If a person has experienced a psychologically traumatic situation in life—for example, a person who may have been captured and tortured—the experience may come back to haunt them in their nightmares. Sleepers may waken in a state of distress and be unable to get back to sleep for some time. Eating before bed, which triggers an increase in the body's metabolism and brain activity, is another potential stimulus for nightmares[1].
Occasional nightmares are commonplace, but recurrent nightmares can interfere with sleep and may cause people to seek medical help. A recently proposed treatment consists of imagery rehearsal.[2] This approach appears to reduce the effects of nightmares and other symptoms in acute stress disorder and post-traumatic stress disorder.[3]
