Editing Insomnia (section)

== Causes ==

While insomnia can be caused by many conditions, it can also occur without any identifiable cause. This is known as Primary Insomnia.<ref>{{cite web | vauthors = Moawad H | date = 2020 | title = Primary insomnia: A lifelong problem | work = Psychiatric Times | url = https://www.psychiatrictimes.com/view/primary-insomnia-lifelong-problem | archive-url = https://web.archive.org/web/20221229175034/https://www.psychiatrictimes.com/view/primary-insomnia-lifelong-problem | archive-date=29 December 2022 | access-date = 29 December 2022 }}</ref> Primary Insomnia may also have an initial identifiable cause but continues after the cause is no longer present. For example, a bout of insomnia may be triggered by a stressful work or life event. However, the condition may continue after the stressful event has been resolved. In such cases, the insomnia is usually perpetuated by the anxiety or fear caused by the sleeplessness itself, rather than any external factors.<ref>{{cite book | vauthors = Meadows G | date = 2015 | title = The sleep book: How to sleep well every night. | location = London, UK | publisher = Orion Publishing Group | page = 21 }}</ref>

Symptoms of insomnia can be caused by or associated with:
*Sleep breathing disorders, such as [[sleep apnea]] or [[upper airway resistance syndrome]]<ref>{{cite book |vauthors=Edinger JD |title=Insomnia, An Issue of Sleep Medicine Clinics |date=2013 |publisher=Elsevier Health Sciences |isbn=978-0-323-18872-2 |page=389 |url=https://books.google.com/books?id=O_cxAgAAQBAJ&pg=PA389 |language=en |access-date=2023-03-19 |archive-date=2023-03-26 |archive-url=https://web.archive.org/web/20230326164814/https://books.google.com/books?id=O_cxAgAAQBAJ&pg=PA389 |url-status=live }}</ref>
*Use of [[psychoactive drug]]s (such as [[stimulant]]s), including certain [[medication]]s, [[herb]]s, [[caffeine]], [[nicotine]], [[cocaine]], [[amphetamine]]s, [[methylphenidate]], [[aripiprazole]], [[MDMA]], [[modafinil]], or excessive alcohol intake<ref name=umm_causes>{{cite web |title=Insomnia |url=http://umm.edu/health/medical/reports/articles/insomnia |publisher=University of Maryland Medical Center |access-date=11 July 2013 |url-status=live |archive-url=https://web.archive.org/web/20130703135611/http://umm.edu/health/medical/reports/articles/insomnia |archive-date=3 July 2013 }}</ref> 
*Use of or withdrawal from alcohol and other [[sedative]]s, such as anti-anxiety and sleep drugs like [[benzodiazepine withdrawal|benzodiazepines]]<ref name=umm_causes/>
*Use of or withdrawal from pain-relievers such as [[opioid withdrawal|opioids]]<ref name="umm_causes" />
*[[Heart disease]]<ref name=comorbidity>{{cite journal | vauthors = Taylor DJ, Mallory LJ, Lichstein KL, Durrence HH, Riedel BW, Bush AJ | title = Comorbidity of chronic insomnia with medical problems | journal = Sleep | volume = 30 | issue = 2 | pages = 213–18 | date = February 2007 | pmid = 17326547 | doi = 10.1093/sleep/30.2.213 | doi-access = free }}</ref>
*[[Restless legs syndrome]], which can cause sleep onset insomnia due to the discomforting sensations felt and the need to move the legs or other body parts to relieve these sensations<ref name=mayo_insomnia_causes>{{cite web |title=Insomnia Causes |url=http://www.mayoclinic.com/health/insomnia/DS00187/DSECTION=causes |publisher=Mayo Clinic |access-date=11 July 2013 |url-status=live |archive-url=https://web.archive.org/web/20131021183326/http://www.mayoclinic.com/health/insomnia/DS00187/DSECTION%3Dcauses |archive-date=21 October 2013 }}</ref> 
*[[Periodic limb movement disorder]] (PLMD), which occurs during sleep and can cause arousals of which the sleeper is unaware<ref>{{cite web |title=Restless Legs Syndrome/Periodic Limb Movement Disorder |url=http://www.nhlbi.nih.gov/health/prof/sleep/res_plan/section5/section5d.html |publisher=National Heart Lung and Blood Institute |access-date=11 July 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130803020537/http://www.nhlbi.nih.gov/health/prof/sleep/res_plan/section5/section5d.html |archive-date=3 August 2013 }}</ref> 
*[[Pain]]:<ref name="Ramakrishnan-2007">{{cite journal | vauthors = Ramakrishnan K, Scheid DC | title = Treatment options for insomnia | journal = American Family Physician | volume = 76 | issue = 4 | pages = 517–26 | date = August 2007 | pmid = 17853625 }}</ref> an injury or condition that causes pain can preclude an individual from finding a comfortable position in which to fall asleep, and can also cause awakening.
*[[Hormone]] shifts such as those that precede [[menstruation]] and those during [[menopause]]<ref name=Santoro2015rev>{{cite journal | vauthors = Santoro N, Epperson CN, Mathews SB | title = Menopausal Symptoms and Their Management | journal = Endocrinology and Metabolism Clinics of North America | volume = 44 | issue = 3 | pages = 497–515 | date = September 2015 | pmid = 26316239 | pmc = 4890704 | doi = 10.1016/j.ecl.2015.05.001 }}</ref>
*Life events such as [[fear]], [[stress (psychology)|stress]], [[anxiety]], emotional or mental tension, work problems, financial stress, birth of a child, and bereavement<ref name=mayo_insomnia_causes />
*Gastrointestinal issues such as heartburn or constipation<ref name=nhlbi_causes>{{cite web |title=What causes insomnia? |url=http://www.nhlbi.nih.gov/health/health-topics/topics/inso/causes.html |publisher=National Heart, Lung, and Blood Institute |access-date=11 July 2013 |url-status=live |archive-url=https://web.archive.org/web/20130703143347/http://www.nhlbi.nih.gov/health/health-topics/topics/inso/causes.html |archive-date=3 July 2013 }}</ref> 
*[[Mental disorder|Mental]], [[Learning Disability|neurobehavioral]], or [[Neurodevelopmental disorder|neurodevelopmental]] disorders such as [[bipolar disorder]], [[clinical depression]], [[generalized anxiety disorder]], [[post traumatic stress disorder]], [[schizophrenia]], [[obsessive compulsive disorder]], [[autism]], [[dementia]],<ref name=Psych4th/>{{rp|326}} [[ADHD]],<ref>{{cite journal | vauthors = Bendz LM, Scates AC | s2cid = 207263711 | title = Melatonin treatment for insomnia in pediatric patients with attention-deficit/hyperactivity disorder | journal = The Annals of Pharmacotherapy | volume = 44 | issue = 1 | pages = 185–91 | date = January 2010 | pmid = 20028959 | doi = 10.1345/aph.1M365 }}</ref> and [[Fetal Alcohol Spectrum Disorder|FASD]]
*Disturbances of the [[circadian rhythm]], such as [[shift work]] and [[jet lag]], can cause an inability to sleep at some times of the day and excessive sleepiness at other times of the day. Chronic [[Circadian rhythm sleep disorder|circadian rhythm disorders]] are characterized by similar symptoms.<ref name=umm_causes/>
* Certain [[Neurology|neurological]] disorders such as [[brain damage|brain lesions]], or a [[Medical history|history]] of [[traumatic brain injury]]<ref>{{cite journal | vauthors = Ouellet MC, Beaulieu-Bonneau S, Morin CM | title = Insomnia in patients with traumatic brain injury: frequency, characteristics, and risk factors | journal = The Journal of Head Trauma Rehabilitation | volume = 21 | issue = 3 | pages = 199–212 | year = 2006 | pmid = 16717498 | doi = 10.1097/00001199-200605000-00001 | s2cid = 28255648 }}</ref>
*[[Disease|Medical conditions]] such as [[hyperthyroidism]]<ref name=NIH2011Ca/>
*Abuse of over-the-counter or prescription sleep aids ([[sedative]] or [[depressant]] drugs) can produce [[rebound insomnia]]<ref name=umm_causes />
*Poor [[sleep hygiene]], e.g., [[Noise health effects|noise]] or over-consumption of caffeine<ref name=umm_causes />
*A rare genetic condition can cause a [[prion]]-based, permanent, and eventually fatal form of insomnia called [[fatal familial insomnia]]<ref name="pmid17406188">{{cite journal | vauthors = Schenkein J, Montagna P | title = Self management of fatal familial insomnia. Part 1: what is FFI? | journal = MedGenMed | volume = 8 | issue = 3 | pages = 65 | date = September 2006 | pmid = 17406188 | pmc = 1781306 }}</ref>
*[[Physical exercise]]: exercise-induced insomnia is common in athletes in the form of prolonged [[sleep onset latency]]<ref>{{cite web | url = http://cev.org.br/biblioteca/the-epidemiological-survey-of-exercise-induced-insomnia-in-chinese-athletes | title = The epidemiological survey of exercise-induced insomnia in Chinese athletes | archive-url = https://web.archive.org/web/20090909095412/http://cev.org.br/biblioteca/the-epidemiological-survey-of-exercise-induced-insomnia-in-chinese-athletes | archive-date = 9 September 2009 | vauthors = Shi Y, Zhou Z, Ning K, Liu J | location = Athens | date = 2004 | work = Pre-Olympic Congress }}</ref>
*Increased exposure to the blue light from artificial sources, such as phones or computers<ref>{{Cite news|url=https://www.scientificamerican.com/article/q-a-why-is-blue-light-before-bedtime-bad-for-sleep/|title=Q&A: Why Is Blue Light before Bedtime Bad for Sleep?|vauthors=Schmerler J|work=Scientific American|access-date=19 October 2018|language=en|archive-date=16 February 2021|archive-url=https://web.archive.org/web/20210216123401/https://www.scientificamerican.com/article/q-a-why-is-blue-light-before-bedtime-bad-for-sleep/|url-status=live}}</ref>
*Chronic pain<ref>{{cite journal | vauthors = Roth T | title = Insomnia: definition, prevalence, etiology, and consequences | journal = Journal of Clinical Sleep Medicine | volume = 3 | issue = 5 Suppl | pages = S7-10 | date = August 2007 | pmid = 17824495 | pmc = 1978319 | doi = 10.5664/jcsm.26929 }}</ref><ref name="nsf">{{Cite web|date=2021|title=What Causes Insomnia?|url=https://www.sleepfoundation.org/insomnia/what-causes-insomnia|access-date=26 February 2021|website=Sleep Foundation|archive-date=15 April 2019|archive-url=https://web.archive.org/web/20190415173039/https://www.sleepfoundation.org/insomnia/what-causes-insomnia|url-status=live}}</ref>
*[[Lower back pain]]<ref name=nsf/>
*[[Asthma]]<ref name=nsf/>

Sleep studies using [[polysomnography]] have suggested that people who have sleep disruption have elevated night-time levels of circulating [[cortisol]] and [[adrenocorticotropic hormone]].<ref>{{cite journal | vauthors = Hirotsu C, Tufik S, Andersen ML | title = Interactions between sleep, stress, and metabolism: From physiological to pathological conditions | journal = Sleep Science | volume = 8 | issue = 3 | pages = 143–152 | date = November 2015 | pmid = 26779321 | pmc = 4688585 | doi = 10.1016/j.slsci.2015.09.002 }}</ref> They also have an elevated metabolic rate, which does not occur in people who do not have insomnia but whose sleep is intentionally disrupted during a sleep study. Studies of brain metabolism using [[positron emission tomography|positron emission tomography (PET) scans]] indicate that people with insomnia have higher metabolic rates by night and by day. The question remains whether these changes are the causes or consequences of long-term insomnia.<ref name=Mendelson>{{Cite journal | vauthors = Mendelson WB |title=New Research on Insomnia: Sleep Disorders May Precede or Exacerbate Psychiatric Conditions |journal=Psychiatric Times |volume=25 |issue=7 |year=2008 |url=http://www.psychiatrictimes.com/insomnia/article/10168/1163082 |url-status=live |archive-url=https://web.archive.org/web/20091019054800/http://www.psychiatrictimes.com/insomnia/article/10168/1163082 |archive-date=19 October 2009 }}</ref>

=== Genetics ===

[[Heritability]] estimates of insomnia vary between 38% in males to 59% in females.<ref name=Lind>{{cite journal | vauthors = Lind MJ, Aggen SH, Kirkpatrick RM, Kendler KS, Amstadter AB | title = A Longitudinal Twin Study of Insomnia Symptoms in Adults | journal = Sleep | volume = 38 | issue = 9 | pages = 1423–30 | date = September 2015 | pmid = 26132482 | pmc = 4531410 | doi = 10.5665/sleep.4982 }}</ref> A [[genome-wide association study]] (GWAS) identified 3 genomic loci and 7 [[genes]] that influence the risk of insomnia and showed that insomnia is highly polygenic.<ref name=Hammerschlag>{{cite journal | vauthors = Hammerschlag AR, Stringer S, de Leeuw CA, Sniekers S, Taskesen E, Watanabe K, Blanken TF, Dekker K, Te Lindert BH, Wassing R, Jonsdottir I, Thorleifsson G, Stefansson H, Gislason T, Berger K, Schormair B, Wellmann J, Winkelmann J, Stefansson K, Oexle K, Van Someren EJ, Posthuma D | title = Genome-wide association analysis of insomnia complaints identifies risk genes and genetic overlap with psychiatric and metabolic traits | journal = Nature Genetics | volume = 49 | issue = 11 | pages = 1584–92 | date = November 2017 | pmid = 28604731 | pmc = 5600256 | doi = 10.1038/ng.3888 }}</ref> In particular, a strong positive association was observed for the [[MEIS1]] gene in both males and females. This study showed that the genetic architecture of insomnia strongly overlaps with psychiatric disorders and metabolic traits.

It has been hypothesized that epigenetics might also influence insomnia through a controlling process of both sleep regulation and brain-stress response, having an impact as well on brain plasticity.<ref name="palagini">{{cite journal | vauthors = Palagini L, Biber K, Riemann D | title = The genetics of insomnia – evidence for epigenetic mechanisms? | journal = Sleep Medicine Reviews | volume = 18 | issue = 3 | pages = 225–35 | date = June 2014 | pmid = 23932332 | doi = 10.1016/j.smrv.2013.05.002 }}</ref>

=== Substance-induced ===

==== Alcohol-induced ====

{{Main|Alcohol use and sleep}}

Alcohol is often used as a form of self-treatment for insomnia to induce sleep. However, alcohol use to induce sleep can be a cause of insomnia. [[Long-term use of alcohol]] is associated with a decrease in [[NREM]] stage 3 and 4 sleep as well as suppression of [[REM sleep]] and REM sleep fragmentation. Frequent moving between sleep stages occurs with awakenings due to headaches, [[polyuria|the need to urinate]], [[dehydration]], and [[diaphoresis|excessive sweating]]. [[Glutamine]] rebound also plays a role when someone is drinking; alcohol inhibits glutamine, one of the body's natural stimulants. When the person stops drinking, the body tries to make up for lost time by producing more glutamine than it needs.

The increase in glutamine levels stimulates the brain while the drinker is trying to sleep, keeping them from reaching the deepest levels of sleep.<ref>{{cite web | vauthors = Perry L | date = 12 October 2004 | url = http://health.howstuffworks.com/hangover5.htm | work = HowStuffWorks | title = How Hangovers Work | archive-url = https://web.archive.org/web/20100315050850/http://health.howstuffworks.com/hangover5.htm | archive-date = 15 March 2010 | access-date = 20 November 2011 }}</ref> Stopping chronic alcohol use can also lead to severe insomnia with vivid dreams. During withdrawal, REM sleep is typically exaggerated as part of a [[rebound effect]].<ref name="sleep_medicine_a04">{{Cite book | vauthors = Lee-chiong T |title=Sleep Medicine: Essentials and Review |date=24 April 2008 |publisher=Oxford University Press|url=https://books.google.com/books?id=s1F_DEbRNMcC&pg=PT105 |isbn=978-0-19-530659-0 |page=105 }}</ref>

====Caffeine====

Some people experience sleep disruption or anxiety if they consume caffeine.<ref>{{cite journal | vauthors = O'Callaghan F, Muurlink O, Reid N | title = Effects of caffeine on sleep quality and daytime functioning | journal = Risk Management and Healthcare Policy | volume = 11 | pages = 263–271 | date = 7 December 2018 | pmid = 30573997 | pmc = 6292246 | doi = 10.2147/RMHP.S156404 | doi-access = free | title-link = doi }}</ref> Doses as low as 100&nbsp;mg/day, such as a {{cvt|6|oz|g}} cup of coffee or two to three {{cvt|12|oz|g}} servings of caffeinated soft-drink, may continue to cause sleep disruption, among other intolerances. Non-regular caffeine users have the least caffeine tolerance for sleep disruption.<ref name="Caffeinedependence JohnHopkins">{{cite web|url=http://www.caffeinedependence.org/caffeine_dependence.html|title=Information about caffeine dependence|date=9 July 2003|website=Caffeinedependence.org|publisher=Johns Hopkins Medicine|archive-url=https://web.archive.org/web/20120523135807/http://www.caffeinedependence.org/caffeine_dependence.html|archive-date=23 May 2012|url-status=usurped|access-date=25 May 2012}}</ref> Some coffee drinkers develop tolerance to its undesired sleep-disrupting effects, but others apparently do not.<ref name="Fredholm">{{cite journal | vauthors = Fredholm BB, Bättig K, Holmén J, Nehlig A, Zvartau EE | title = Actions of caffeine in the brain with special reference to factors that contribute to its widespread use | journal = Pharmacological Reviews | volume = 51 | issue = 1 | pages = 83–133 | date = March 1999 | doi = 10.1016/S0031-6997(24)01396-6 | pmid = 10049999 }}</ref>

==== Benzodiazepine-induced ====

Like alcohol, [[benzodiazepine]]s, such as [[alprazolam]], [[clonazepam]], [[lorazepam]], and [[diazepam]], are commonly used to treat insomnia in the short-term (both prescribed and self-medicated), but worsen sleep in the long-term. While benzodiazepines can put people to sleep (i.e., inhibit NREM stage 1 and 2 sleep), while asleep, the drugs disrupt [[sleep architecture]]: decreasing sleep time, delaying time to REM sleep, and decreasing deep [[slow-wave sleep]] (the most restorative part of sleep for both energy and mood).<ref>{{cite journal | vauthors = Ashton H | s2cid = 1709063 | title = The diagnosis and management of benzodiazepine dependence | journal = Current Opinion in Psychiatry | volume = 18 | issue = 3 | pages = 249–55 | date = May 2005 | pmid = 16639148 | doi = 10.1097/01.yco.0000165594.60434.84 }}</ref><ref>{{cite journal | vauthors = Morin CM, Bélanger L, Bastien C, Vallières A | title = Long-term outcome after discontinuation of benzodiazepines for insomnia: a survival analysis of relapse | journal = Behaviour Research and Therapy | volume = 43 | issue = 1 | pages = 1–14 | date = January 2005 | pmid = 15531349 | doi = 10.1016/j.brat.2003.12.002 }}</ref><ref>{{cite journal | vauthors = Poyares D, Guilleminault C, Ohayon MM, Tufik S | title = Chronic benzodiazepine usage and withdrawal in insomnia patients | journal = Journal of Psychiatric Research | volume = 38 | issue = 3 | pages = 327–34 | date = 1 June 2004 | pmid = 15003439 | doi = 10.1016/j.jpsychires.2003.10.003 }}</ref>

==== Opioid-induced ====
[[Opioid]] medications such as [[hydrocodone]], [[oxycodone]], and [[morphine]] are used for insomnia that is associated with [[pain]] due to their [[analgesic]] properties and [[hypnotic]] effects. Opioids can fragment sleep and decrease [[Rapid eye movement sleep|REM]] and [[Non-rapid eye movement sleep|stage 2]] sleep. By producing [[analgesia]] and [[sedation]], opioids may be appropriate in carefully selected patients with pain-associated insomnia.<ref name="Ramakrishnan-2007" /> However, dependence on opioids can lead to long-term sleep disturbances.<ref>{{Cite journal | vauthors = Asaad TA, Ghanem MH, Samee AM, El-Habiby MM |s2cid=76376646 |title=Sleep Profile in Patients with Chronic Opioid Abuse |doi=10.1097/ADT.0b013e3181fb2847 |journal=Addictive Disorders & Their Treatment |volume=10 |pages=21–28 |year=2011 }}</ref>

=== Risk factors ===

Insomnia affects people of all age groups, but people in the following groups have a higher chance of acquiring insomnia:<ref>{{Cite news|url=https://www.mayoclinic.org/diseases-conditions/insomnia/symptoms-causes/syc-20355167|title=Insomnia – Symptoms and causes|work=Mayo Clinic|access-date=5 February 2018|language=en|archive-date=24 January 2018|archive-url=https://web.archive.org/web/20180124135326/https://www.mayoclinic.org/diseases-conditions/insomnia/symptoms-causes/syc-20355167|url-status=live}}</ref>
*Individuals older than 60
*History of mental health disorders, including depression, etc.
*Emotional stress
*Working late-night shifts
*Traveling through different time zones<ref name=Pun2012/>
*Having chronic diseases such as [[diabetes]], kidney disease, lung disease, [[Alzheimer's]], or heart disease<ref>{{Cite news|url=http://www.winchesterhospital.org/health-library/article?id=19705|title=Risk Factors For Insomnia|access-date=14 April 2019|language=en|archive-date=19 February 2020|archive-url=https://web.archive.org/web/20200219030647/https://www.winchesterhospital.org/health-library/article?id=19705|url-status=dead}}</ref> 
*[[Alcohol (drug)|Alcohol]] or drug use disorders 
*Gastrointestinal reflux disease
*Heavy smoking
*Work stress<ref>{{cite book | vauthors = Lichstein KL, Taylor DJ, McCrae CS, Ruiter ME | chapter = Insomnia: epidemiology and risk factors. | title = Principles and Practice of Sleep Medicine | edition = Fifth | date = November 2010 | pages = 827–837 | publisher = Elsevier Inc. | doi = 10.1016/B978-1-4160-6645-3.00076-1 }}</ref>
*Individuals of low socioeconomic status<ref name="Billings_2021">{{cite journal | vauthors = Billings ME, Cohen RT, Baldwin CM, Johnson DA, Palen BN, Parthasarathy S, Patel SR, Russell M, Tapia IE, Williamson AA, Sharma S | title = Disparities in Sleep Health and Potential Intervention Models: A Focused Review | journal = Chest | volume = 159 | issue = 3 | pages = 1232–1240 | date = March 2021 | pmid = 33007324 | pmc = 7525655 | doi = 10.1016/j.chest.2020.09.249 }}</ref>
*Urban Neighborhoods<ref name="Billings_2021" />
*Household stress<ref name="Billings_2021" />