Sleep deprivation

===Treating depression===
{{Further|Sleep Deprivation Therapy}}
Studies show that sleep restriction has some potential for treating [[Major depressive disorder|depression]].<ref name="Sleep and depression review"/> Those with depression tend to have earlier occurrences of REM sleep with an increased number of rapid eye movements; therefore, monitoring patients' EEG and awakening them during occurrences of REM sleep appear to have a [[therapeutic effect]], alleviating depressive symptoms.<ref>{{Cite book| vauthors = Carlson N |title=Physiology of Behavior|publisher=Pearson|year=2013|isbn=978-0-205-23939-9|edition=11th|location=Boston|pages=578–579}}</ref> This kind of treatment is known as [[wake therapy]]. Although as many as 60% of patients show an immediate recovery when sleep-deprived, most patients relapse the following night. The effect has been shown to be linked to an increase in [[brain-derived neurotrophic factor]] (BDNF).<ref>{{cite journal | vauthors = Gorgulu Y, Caliyurt O | title = Rapid antidepressant effects of sleep deprivation therapy correlates with serum BDNF changes in major depression | journal = Brain Research Bulletin | volume = 80 | issue = 3 | pages = 158–162 | date = September 2009 | pmid = 19576267 | doi = 10.1016/j.brainresbull.2009.06.016 | s2cid = 7672556 }}</ref>  A comprehensive evaluation of the human [[metabolome]] in sleep deprivation in 2014 found that 27 metabolites are increased after 24 waking hours and suggested [[serotonin]], tryptophan, and taurine may contribute to the antidepressive effect.<ref>{{cite journal | vauthors = Davies SK, Ang JE, Revell VL, Holmes B, Mann A, Robertson FP, Cui N, Middleton B, Ackermann K, Kayser M, Thumser AE, Raynaud FI, Skene DJ | title = Effect of sleep deprivation on the human metabolome | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 111 | issue = 29 | pages = 10761–10766 | date = July 2014 | pmid = 25002497 | pmc = 4115565 | doi = 10.1073/pnas.1402663111 | bibcode = 2014PNAS..11110761D | doi-access = free }}</ref>

The incidence of relapse can be decreased by combining sleep deprivation with medication or a combination of [[light therapy]] and phase advance (going to bed substantially earlier than one's normal time).<ref name="Ncbi">{{cite journal | vauthors = Wirz-Justice A, Van den Hoofdakker RH | title = Sleep deprivation in depression: what do we know, where do we go? | journal = Biological Psychiatry | volume = 46 | issue = 4 | pages = 445–453 | date = August 1999 | pmid = 10459393 | doi = 10.1016/S0006-3223(99)00125-0 | s2cid = 15428567 }}</ref><ref>{{cite journal | vauthors = Wirz-Justice A, Benedetti F, Berger M, Lam RW, Martiny K, Terman M, Wu JC | title = Chronotherapeutics (light and wake therapy) in affective disorders | journal = Psychological Medicine | volume = 35 | issue = 7 | pages = 939–944 | date = July 2005 | pmid = 16045060 | doi = 10.1017/S003329170500437X | doi-access = free }}</ref> Many [[tricyclic antidepressants]] suppress REM sleep, providing additional evidence for a link between [[mood (psychology)|mood]] and sleep.<ref name="SleepDepEmedicinehealth">{{cite web | url = http://www.emedicinehealth.com/articles/42677-5.asp | title = Disorders That Disrupt Sleep (Parasomnias) | archive-url = https://web.archive.org/web/20051222202250/http://www.emedicinehealth.com/articles/42677-5.asp| archive-date=22 December 2005 | work = eMedicineHealth }}</ref> Similarly, [[tranylcypromine]] has been shown to completely suppress REM sleep at adequate doses.