Somnolence (alternatively " sleepiness" or " drowsiness") is a state of strong desire for sleep, or sleeping for unusually long periods (cf. hypersomnia). It has two distinct meanings, referring both to the usual state preceding falling asleep, and the chronic condition referring to being in that state independent of a [1 ] circadian rhythm. "Somnolence" is derived from the Latin "somnus" meaning "sleep."
Hazards [ edit ]
Sleepiness can be dangerous when performing tasks that require constant concentration, such as driving a
vehicle. When a person is sufficiently fatigued, microsleeps may be experienced.
Illness [ edit ]
The human body can become sleepy in response to
infection. Such somnolence is one of several [2 ] sickness behaviors 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. [3 ] [4 ]
Diagnosis [ edit ]
A number of diagnostic tests, including the
Epworth Sleepiness Scale, are available to help ascertain the seriousness and likely causes of abnormal somnolence.
Associated conditions [ edit ]
advanced sleep phase disorder
Alice in Wonderland syndrome
chronic fatigue syndrome
circadian rhythm sleep disorder
clinical depression, especially seasonal affective disorder (SAD)
delayed sleep phase syndrome
diabetes – ketoacidosis as example, but not balanced diabetes mellitus
encephalitis – (viral, bacterial or other agents)
epilepsy – after seizure
infectious mononucleosis (glandular fever)
intracranial hemorrhage such as due to ruptured aneurysm increased
intracranial pressure; for example, due to brain tumors
lyme disease (borreliosis)
analgesics – mostly prescribed or illicit opiates such as OxyContin or heroin anticonvulsants /
antiepileptics – such as phenytoin (Dilantin), carbamazepine (Tegretol), Lyrica (pregbalin), Gabapentin
antidepressants – for instance sedating tricyclic antidepressants, and [5 ] mirtazapine. Somnolence is less common with SSRIs and [6 ] SNRIs as well as MAOIs.
antihistamines – for instance, diphenhydramine ( Benadryl, Nytol) and doxylamine (Unisom-2)
antipsychotics – for example, thioridazine, quetiapine (Seroquel), olanzapine (Zyprexa), risperidone, and ziprasidone ( Geodon) but not haloperidol
dopamine agonists used in the treatment of Parkinson's disease – e.g. pergolide, ropinirole and pramipexole.
HIV medications – for example, Sustiva and efavirenz
hypertension medications – such as amlodipine
tranquilizers / hypnotics – such as zopiclone (Zimovane), or the benzodiazepines such as diazepam (Valium) or nitrazepam (Mogadon) and the barbiturates, such as amobarbital (Amytal) or secobarbital (Seconal) other agents impacting the
central nervous system in sufficient or toxic doses
non-24-hour sleep–wake disorder aka hypernychthemeral disorder aka free running disorder (FRD)
sleep deprivation / insomnia
traumatic brain injury
African trypanosomiasis ("sleeping sickness")
See also [ edit ]
References [ edit ]
^ Bereshpolova, Y.; Stoelzel, C. R.; Zhuang, J.; Amitai, Y.; Alonso, J.-M.; Swadlow, H. A. (2011). "Getting Drowsy? Alert/Nonalert Transitions and Visual Thalamocortical Network Dynamics". Journal of Neuroscience 31 (48): 17480–7. doi: 10.1523/JNEUROSCI.2262-11.2011. PMID 22131409.
^ Mullington, Janet; Korth, Carsten; Hermann, Dirk M.; Orth, Armin; Galanos, Chris; Holsboer, Florian; Pollmächer, Thomas (2000). "Dose-dependent effects of endotoxin on human sleep". American Journal of Physiology – Regulatory, Integrative and Comparative Physiology 278 (4): R947–55. PMID 10749783.
^ Hart, Benjamin L. (1988). "Biological basis of the behavior of sick animals". Neuroscience & Biobehavioral Reviews 12 (2): 123–37. doi: 10.1016/S0149-7634(88)80004-6. PMID 3050629.
^ Kelley, Keith W.; Bluthé, Rose-Marie; Dantzer, Robert; Zhou, Jian-Hua; Shen, Wen-Hong; Johnson, Rodney W.; Broussard, Suzanne R. (2003). "Cytokine-induced sickness behavior". Brain, Behavior, and Immunity 17 (1): 112–118. doi: 10.1016/S0889-1591(02)00077-6. PMID 12615196.
^ Zimmermann, C.; Pfeiffer, H. (2007). "Schlafstörungen bei Depression". Der Nervenarzt 78 (1): 21–30. doi: 10.1007/s00115-006-2111-1. PMID 16832696.
^ Watanabe, Norio; Omori, Ichiro M; Nakagawa, Atsuo; Cipriani, Andrea; Barbui, Corrado; Churchill, Rachel; Furukawa, Toshi A (2011). "Mirtazapine versus other antidepressive agents for depression". Cochrane Database of Systematic Reviews (12): CD006528. doi: 10.1002/14651858.CD006528.pub2. PMC 4158430. PMID 22161405.