sundowning

sundown +‎ -ing

sundowning (uncountable)

1. (medicine, psychology, psychiatry) A state of agitation, confusion, or delirium, especially in patients suffering from Alzheimer's disease, which begins daily at nightfall and which is alleviated by daylight.
   • 1986, Norma Sullivan; Barry Fogel, “Could This Be Delirium?”, in The American Journal of Nursing, volume 86, number 12, page 1363:

     Impaired judgment and sundowning (increased confusion when orienting cues diminish at night) often makes it necessary to restrict and protect the delirious patient.

• nocturnal delirium
• sundowner syndrome

• sundowner

sundowning

1. present participle of sundown

• seasonal affective disorder