Editing Somnolence (section)

=== Physical illness ===
Sleepiness can also be a response to infection.<ref>{{cite journal |first1=Janet |last1=Mullington |first2=Carsten |last2=Korth |first3=Dirk M. |last3=Hermann |first4=Armin |last4=Orth |first5=Chris |last5=Galanos |first6=Florian |last6=Holsboer |first7=Thomas |last7=Pollmächer |title=Dose-dependent effects of endotoxin on human sleep |journal=American Journal of Physiology. Regulatory, Integrative and Comparative Physiology |volume=278 |issue=4 |pages=R947–55 |year=2000 |pmid=10749783 |doi=10.1152/ajpregu.2000.278.4.r947|s2cid=10272455 }}</ref> Such somnolence is one of several [[sickness behavior]]s or reactions to infection that some theorize evolved to promote recovery by conserving energy while the body fights the infection using fever and other means.<ref name="Hart">{{cite journal |doi=10.1016/S0149-7634(88)80004-6|title=Biological basis of the behavior of sick animals|journal=Neuroscience & Biobehavioral Reviews|volume=12|issue=2|pages=123–37|year=1988|last1=Hart|first1=Benjamin L.|pmid=3050629|s2cid=17797005}}</ref><ref>{{cite journal |doi=10.1016/S0889-1591(02)00077-6|title=Cytokine-induced sickness behavior|journal=Brain, Behavior, and Immunity|volume=17|pages=112–118|year=2003|last1=Kelley|first1=Keith W.|last2=Bluthé|first2=Rose-Marie|last3=Dantzer|first3=Robert|last4=Zhou|first4=Jian-Hua|last5=Shen|first5=Wen-Hong|last6=Johnson|first6=Rodney W.|last7=Broussard|first7=Suzanne R.|pmid=12615196|issue=1|s2cid=25400611}}</ref> Other causes include:<ref>{{Cite web|title = Drowsiness: MedlinePlus Medical Encyclopedia|url = https://www.nlm.nih.gov/medlineplus/ency/article/003208.htm|website = www.nlm.nih.gov|access-date = 2015-10-31}}</ref>
* [[Anxiety]] 
* [[Brain tumor]]
* [[Chronic pain]]s
* [[Concussion]] – a mild traumatic brain injury 
* [[Diabetes]]
* [[Fibromyalgia]]
* [[Head injury]]
* [[Hypercalcemia]] – too much calcium in the blood
* [[Hypermagnesemia]]
* [[Hyponatremia]] – low blood sodium 
* [[Hypothyroidism]] – the body doesn't produce enough hormones that control how cells use energy
* [[Meningitis]]
* [[Mood disorder]]s – [[Depression (mood)|depression]]
* [[Multiple sclerosis]] 
* [[Narcolepsy]] – disorder of the nervous system
* [[Skull fracture]]s
* [[African trypanosomiasis|Sleeping sickness]] – caused by a specific parasite
* [[Stress (biology)|Stress]]