|Classification and external resources|
Somnolence (alternatively "sleepiness" or "drowsiness") is a state of strong desire for sleep, or sleeping for unusually long periods (cf. hypersomnia). It has distinct meanings. It can refer to the usual state preceding falling asleep; the condition of being in a drowsy state due to circadian rhythm disorders; or as a symptom of health problems. It can be accompanied by lethargy, weakness, and lack of mental agility. 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. "Somnolence" is derived from the Latin "somnus" meaning "sleep."
- Circadian rhythm disorders 1.1
- Other causes 1.2
- Medications that may cause drowsiness 1.3
- Diagnosis 2
- Treatment 3
- Associated conditions 4
- See also 5
- References 6
Circadian rhythm disorders
Circadian rhythm disorders are a common cause of drowsiness as are a number of other conditions such as sleep apnea, insomnia, and narcolepsy.
Sleepiness can also be a response to infection. Such somnolence is one of several 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. Other causes include:
- Sleeping sickness – caused by a specific parasite
- Hypothyroidism – When the body doesn't produce enough hormones that control how cells use energy
- Low blood sodium – Hyponatremia
- Hypercalcemia – Too much calcium in the blood
- Head Injury
- Concussion – A mild traumatic brain injury
- Narcolepsy – disorder of the nervous system
- Brain tumor
- Skull fractures
- Chronic pains
- Mood disorders – Depression, Anxiety, Stress
Medications that may cause drowsiness
- 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 mirtazapine. Somnolence is less common with SSRIs and 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 – such as 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
A number of diagnostic tests, including the Epworth Sleepiness Scale, are available to help ascertain the seriousness and likely causes of abnormal somnolence.
Somnolence is a symptom, so the treatment will depend on its cause. If the cause is the behavior and life choices of the patient (like working long hours, smoking, mental state), it may help to get plenty of rest and get distractions. It’s also important to investigate what’s causing the problem, such as stress or anxiety, and take steps to reduce the feeling.
- Alice in Wonderland syndrome
- brain edema
- cerebral hypoxia
- chronic fatigue syndrome
- circadian rhythm sleep disorders
- clinical depression, including seasonal affective disorder (SAD)
- diabetes – ketoacidosis as an example, but not balanced diabetes mellitus
- encephalitis – (viral, bacterial or other agents)
- epilepsy – after seizure
- idiopathic hypersomnia
- infectious mononucleosis (glandular fever)
- intracranial hemorrhage such as due to ruptured aneurysms
- increased intracranial pressure; for example, due to brain tumors
- lyme disease (borreliosis)
- sickness behavior
- sleep apnea
- sleep deprivation
- traumatic brain injury
- African trypanosomiasis ("sleeping sickness")
- 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.
- "Drowsiness - Symptoms, Causes, Treatments". www.healthgrades.com. Retrieved 2015-10-31.
- 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.
- Hart, Benjamin L. (1988). "Biological basis of the behavior of sick animals". Neuroscience & Biobehavioral Reviews 12 (2): 123–37.
- 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.
- "Drowsiness: Causes, Treatments & Prevention". www.healthline.com. Retrieved 2015-10-31.
- "Drowsiness: MedlinePlus Medical Encyclopedia". www.nlm.nih.gov. Retrieved 2015-10-31.
- Zimmermann, C.; Pfeiffer, H. (2007). "Schlafstörungen bei Depression". Der Nervenarzt 78 (1): 21–30.
- 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.
- Carskadon, M.A.; Dement, W.C.; Mitler, M.M.; Roth, T.; Westbrook, P.R.; Keenan, S. Guidelines for the Multiple Sleep Latency Test (MSLT): a standard measure of sleepiness. Sleep 1986; 9:519–524
- Johns, MW (March 2000). "Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the epworth sleepiness scale: failure of the MSLT as a gold standard". Journal of Sleep Research 9 (1): 5–11.