The term "sundowner," which is not a medical term, has been applied to people who tend to become increasingly confused at the end of the day and into the night. This phenomenon usually occurs in the presence of dementia or delirium. The cause is not known but may be related to fatigue. In addition, confusion may be aggravated by reduced visual stimulation when darkness falls.

People who experience an increase in confusion and disorientation after dark may be helped by night-lights that are bright enough to improve orientation as to place and surroundings. For those in an unfamiliar setting such as a hospital or care center, adding familiar items from home such as a favorite chair, pictures, and a radio may be of benefit as well.

The phenomenon of confusion at sundown does not represent a specific diagnosis and should not be considered a disease or syndrome.