Somnolence (or "drowsiness", or "hypersomnia") is a state of near-sleep, a strong desire for sleep, or sleeping unusually long periods. 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 circadian rhythm. The disorder characterised by the latter condition is most commonly associated with users of prescription hypnotics, such as Mirtazapine or Zolpidem.

It is considered a lesser impairment of consciousness than stupor or coma.

Associated conditions

• sleep apnea, mostly due to obesity
• narcolepsy
• pharmaca

tranquilizers

hypnotics

some antipsychotics. For example: thioridazine but not haloperidol.

some analgesics

some antiepileptics

some antihistamines

generally many other agents with impact on central nervous system in sufficient doses

• clinical depression, especially seasonal affective disorder or SAD
• increased intracranial pressure

intracranial tumors

stroke

trauma to the brain

brain edema

any other intracranial bleeding such as due to ruptured aneurysm

hydrocephalus

encephalitis - (viral, bacterial or other agens)

and many others

See also

• insomnia
• hypersomnia
• dyssomnia

Diseases