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.

   • 2023 April, Abhijit Satpati, Thomas Neylan, Lea T. Grinberg, “Histaminergic neurotransmission in aging and Alzheimer's disease: A review of therapeutic opportunities and gaps”, in Alzheimer’s & Dementia: Translational Research & Clinical Interventions‎, volume 9, number 2, Wiley, →DOI, →ISSN:

     Polysomnography and othersleep measures show sleep fragmentation with shortening of N3 sleep togetherwith excessive daytime sleepiness (EDS) and sundowning as the main findings in AD patients.

• nocturnal delirium
• sundowner syndrome

• sundowner

sundowning

1. present participle and gerund of sundown

• seasonal affective disorder