Quick summary

Sundown syndrome is a term that describes the onset of confusion and agitation that generally affects people with dementia or cognitive impairment and ususally strikes around sunset. Many people, though, use the term to loosely describe increased agitation and confusion that can occur anytime but may be more noticeable in the late afternoon or early evening.

Although researchers equate sundown syndrome with dementia, people without dementia sometimes develop delirious and agitated behavior in the hospital as a reaction to pain, medical procedures, or infection.