Sleep deprivation

=== Mood ===
Sleep deprivation can have a negative impact on mood.<ref>{{cite journal | vauthors = Kramer M, Roehrs T, Roth T | title = Mood change and the physiology of sleep | journal = Comprehensive Psychiatry | volume = 17 | issue = 1 | pages = 161–165 | date = January 1976 | pmid = 174865 | doi = 10.1016/0010-440x(76)90065-1 }}</ref> Staying up all night or taking an unexpected night shift can make one feel irritable. Once one catches up on sleep, one's mood will often return to baseline or normal. Even partial sleep deprivation can have a significant impact on mood. In one study, subjects reported increased sleepiness, fatigue, confusion, tension, and total mood disturbance, which all recovered to their baseline after one to two full nights of sleep.<ref name=":0">{{Cite web|title=Sleep and Mood {{!}} Need Sleep|url=http://healthysleep.med.harvard.edu/need-sleep/whats-in-it-for-you/mood#1.|access-date=21 January 2021|website=healthysleep.med.harvard.edu|archive-date=21 March 2021|archive-url=https://web.archive.org/web/20210321052445/http://healthysleep.med.harvard.edu/need-sleep/whats-in-it-for-you/mood#1.|url-status=dead}}</ref><ref>{{cite journal | vauthors = Dinges DF, Pack F, Williams K, Gillen KA, Powell JW, Ott GE, Aptowicz C, Pack AI | title = Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night | journal = Sleep | volume = 20 | issue = 4 | pages = 267–277 | date = April 1997 | pmid = 9231952 }}</ref>

[[Depression (mood)|Depression]] and sleep are in a bidirectional relationship. Poor sleep can lead to the development of depression, and depression can cause [[insomnia]], [[hypersomnia]], or [[obstructive sleep apnea]].<ref>{{Cite web|title=Depression and Sleep|url=https://www.sleepfoundation.org/mental-health/depression-and-sleep|access-date=21 January 2021|website=Sleep Foundation |date=18 September 2020 |language=en}}</ref><ref>{{cite journal | vauthors = Franzen PL, Buysse DJ | title = Sleep disturbances and depression: risk relationships for subsequent depression and therapeutic implications | journal = Dialogues in Clinical Neuroscience | volume = 10 | issue = 4 | pages = 473–481 | date = 2008 | pmid = 19170404 | pmc = 3108260 | doi = 10.31887/DCNS.2008.10.4/plfranzen }}</ref> About 75% of adult patients with depression can present with insomnia.<ref>{{cite journal | vauthors = Nutt D, Wilson S, Paterson L | title = Sleep disorders as core symptoms of depression | journal = Dialogues in Clinical Neuroscience | volume = 10 | issue = 3 | pages = 329–336 | date = 2008 | pmid = 18979946 | pmc = 3181883 | doi = 10.31887/DCNS.2008.10.3/dnutt }}</ref> Sleep deprivation, whether total or not, can induce significant anxiety, and longer sleep deprivations tend to result in an increased level of anxiety.<ref>{{cite journal | vauthors = Pires GN, Bezerra AG, Tufik S, Andersen ML | title = Effects of acute sleep deprivation on state anxiety levels: a systematic review and meta-analysis | journal = Sleep Medicine | volume = 24 | pages = 109–118 | date = August 2016 | pmid = 27810176 | doi = 10.1016/j.sleep.2016.07.019 }}</ref>

Sleep deprivation has also shown some positive effects on mood and can be used to treat depression.<ref name="Sleep and depression review" /> Chronotype can affect how sleep deprivation influences mood. Those with morningness (advanced sleep period or "lark") preference become more depressed after sleep deprivation, while those with eveningness (delayed sleep period or "owl") preference show an improvement in mood.<ref>{{cite journal | vauthors = Selvi Y, Gulec M, Agargun MY, Besiroglu L | title = Mood changes after sleep deprivation in morningness-eveningness chronotypes in healthy individuals | journal = Journal of Sleep Research | volume = 16 | issue = 3 | pages = 241–244 | date = September 2007 | pmid = 17716271 | doi = 10.1111/j.1365-2869.2007.00596.x | url = http://dl.dropboxusercontent.com/u/85192141/2006-selvi.pdf | url-status = live | s2cid = 42338269 | doi-access = free | archive-url = https://web.archive.org/web/20141215025258/https://dl.dropboxusercontent.com/u/85192141/2006-selvi.pdf | archive-date = 15 December 2014 }}</ref>

Mood and mental states can affect sleep as well. Increased agitation and arousal from anxiety or stress can keep one more aroused, awake, and alert.<ref name=":0" />