Editing Mood (psychology) (section)

===Lack of sleep===

[[Sleep]] has a complex, and as yet not fully elucidated, relationship with mood. Most commonly if a person is sleep deprived he/she will become more irritable, angry, more prone to stress, and less energized throughout the day. "Studies have shown that even partial sleep deprivation has a significant effect on mood. University of Pennsylvania researchers found that subjects who were limited to only 4.5 hours of sleep a night for one week reported feeling more stressed, angry, sad, and mentally exhausted. When the subjects resumed normal sleep, they reported a dramatic improvement in mood."<ref>Dr. Lawrence J. Epstein</ref> Generally, evening oriented people, as compared to morning ones, show decreased energy and pleasantness and heightened tension.<ref>{{cite journal | last1 = Jankowski | first1 = K.S. | year = 2014 | title = The role of temperament in the relationship between morningness-eveningness and mood | journal = Chronobiology International | volume = 31 | issue = 1| pages = 114–22 | doi=10.3109/07420528.2013.829845| pmid = 24144242 | s2cid = 12007427 }}</ref>

However, in a subset of cases sleep deprivation can, paradoxically, lead to increased energy and alertness and enhanced mood. This effect is most marked in persons with an eveningness type (so called night-owls) and people suffering from depression. For this reason it has sometimes been used as a treatment for [[major depressive disorder]].<ref name="REM deprivation in healthy people">{{cite journal |author=Nykamp K, Rosenthal L, Folkerts M, Roehrs T, Guido P, Roth, T |title=The effects of REM sleep deprivation on the level of sleepiness/alertness |journal=Sleep |volume=21 |issue=6 |pages=609–14 |date=September 1998 |pmid=9779520|last2=Rosenthal |last3=Folkerts |last4=Roehrs |last5=Guido |last6=Roth |doi=10.1093/sleep/21.6.609 |doi-access=free }}</ref><ref name="Sleep and depression review">{{cite journal |author=Riemann D, Berger M, Voderholzer U |title=Sleep and depression – results from psychobiological studies: an overview |journal=Biological Psychology |volume=57 |issue=1–3 |pages=67–103 |date=July–August 2001 |pmid=11454435 |doi=10.1016/s0301-0511(01)00090-4|last2=Berger |last3=Voderholzer |s2cid=31725861 }}</ref>