Nightmare

After a nightmare, a person will often awaken in a state of distress and may be unable to return to sleep for a short period of time.

Eating before going to sleep, which triggers an increase in the body's metabolism and brain activity, can be a potential stimulus for nightmares.

The word nightmare is derived from the Old English mare, a mythological demon or goblin who torments others with frightening dreams.

[6] The mare of Germanic and Slavic folklore were thought to ride on people's chests while they sleep, causing nightmares.

[9] Nightmare disorder symptoms include repeated awakenings from the major sleep period or naps with detailed recall of extended and extremely frightening dreams, usually involving threats to survival, security, or self-esteem.

[4] According to the clinical studies the content can include being chased, injury or death of others, falling, natural disasters or accidents.

Lucid-dreaming advocate Stephen LaBerge has outlined a possible reason for how dreams are formulated and why nightmares occur.

To LaBerge, a dream starts with an individual thought or scene, such as walking down a dimly lit street.

There is a view, possibly featured in the story A Christmas Carol, that eating cheese before sleep can cause nightmares, but there is little scientific evidence for this.

[20][21][22] Sigmund Freud and Carl Jung seemed to have shared a belief that people frequently distressed by nightmares could be re-experiencing some stressful event from the past.

Research has found that this technique not only reduces the occurrence of nightmares and insomnia[25] but also improves other daytime PTSD symptoms.