Editing Nightmare (section)

==Cause==
Scientific research shows that nightmares may have many causes. In a study focusing on children, researchers were able to conclude that nightmares directly correlate with the stress in children's lives. Children who experienced the death of a family member or a close friend or know someone with a chronic illness have more frequent nightmares than those who are only faced with stress from school or stress from social aspects of daily life.<ref>Schredl, Michael, et al. "Nightmares and Stress in Children." Sleep and Hypnosis 10.1 (2008): 19–25. ProQuest. Web. 29 April 2014.</ref>
A study researching the causes of nightmares focuses on patients who have [[sleep apnea]]. The study was conducted to determine whether or not nightmares may be caused by sleep apnea, or being unable to breathe. In the nineteenth century, authors believed that nightmares were caused by not having enough oxygen, therefore it was believed that those with sleep apnea had more frequent nightmares than those without it. The results actually showed that healthy people have more nightmares than sleep apnea patients.<ref>Schredl, Michael, et al. "Nightmares and Oxygen Desaturations: Is Sleep Apnea Related to Heightened Nightmare Frequency?" Sleep and Breathing 10.4 (2006): 203–209. ProQuest. Web. 24 April 2014.</ref>
Another study supports the hypothesis. In this study, 48 patients (aged 20–85 yrs) with [[Obstructive lung disease|obstructive airways disease]] (OAD), including 21 with and 27 without asthma, were compared with 149 sex- and age-matched controls without respiratory disease. OAD subjects with asthma reported approximately 3 times as many nightmares as controls or OAD subjects without asthma.<ref>{{cite journal |last1=Wood |first1=James M. |last2=Bootzin |first2=Richard R. |last3=Quan |first3=Stuart F. |last4=Klink |first4=Mary E. |title=Prevalence of nightmares among patients with asthma and chronic obstructive airways disease. |journal=Dreaming |date=December 1993 |volume=3 |issue=4 |pages=231–241 |doi=10.1037/h0094382 |id={{ProQuest|1023291364}} {{EBSCOhost|1994-18130-001|dbcode=pdh}} }}</ref> The evolutionary purpose of nightmares then could be a mechanism to awaken a person who is in danger.

[[Lucid dream|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. Since dreams are not predetermined, the brain responds to the situation by either thinking a good thought or a bad thought, and the dream framework follows from there. If bad thoughts in a dream are more prominent than good thoughts, the dream may proceed to be a nightmare.<ref>{{Cite book|title=Exploring the World of Lucid Dreaming|last=Stephen|first=LaBerge|publisher=Ballantine Books|year=1990|location=New York|pages=65–66}}</ref>

{{Anchor|cheese}}
[[File:Dream of the Rarebit Fiend 1905-02-25 (cropped).jpg|thumb|A panel from the early 20th century comic ''[[Dream of the Rarebit Fiend]]'', whose protagonists regularly suffer nightmares after eating [[cheese]].]]
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.<ref>{{cite news|last=Hammond|first=Claudia|date=17 April 2012|title=Does cheese give you nightmares?|work=BBC|url=http://www.bbc.com/future/story/20120417-does-cheese-give-you-nightmares|access-date=7 October 2018}}</ref> A single, biased study conducted by the British Cheese Board in 2005 argued that consuming cheese could trigger more vivid dreams, but this study was not backed up with sufficient research, and contradicts existing studies which found that consuming dairy products is associated with better overall sleep quality.<ref>{{Cite web |title=Does cheese really give you vivid dreams? |url=https://www.bbc.com/future/article/20211117-does-cheese-really-give-you-vivid-dreams |access-date=2024-03-17 |website=www.bbc.com}}</ref>

Severe nightmares are also likely to occur when a person has a [[fever]]; these nightmares are often referred to as fever dreams. 

Recent research has shown that frequent nightmares may precede the development of neurodegenerative diseases, such as [[Parkinson's disease]] and [[dementia]].<ref name="Otaiku2022a">{{cite journal | author = Otaiku, Abidemi | year = 2022 | title = Distressing dreams and risk of Parkinson's disease: A population-based cohort study | journal = eClinicalMedicine | volume =  8| issue = 48| doi = 10.1016/j.eclinm.2022.101474 | pmid = 35783487 | pmc = 9249554 }}</ref><ref name="Otaiku2022b">{{cite journal | author = Otaiku, Abidemi | year = 2022 | title = Distressing dreams, cognitive decline, and risk of dementia: A prospective study of three population-based cohorts | journal = eClinicalMedicine | volume =  21| issue = 52| doi = 10.1016/j.eclinm.2022.101640 | pmid = 36313147 | pmc = 9596309 }}</ref><ref name="Otaiku2023">{{cite journal | author = Otaiku, Abidemi | year = 2023 | title = Distressing dreams in childhood and risk of cognitive impairment or Parkinson's disease in adulthood: a national birth cohort study | journal = eClinicalMedicine | volume =  8| issue = 48| doi = 10.1016/j.eclinm.2023.101872 | pmid = 37064510 | pmc = 10102896 }}</ref>