Sundowning was first described almost 80 years ago as nocturnal dementia. It still remains one of the least understood phenomena. There have been multiple definitions described but there is no general consensus. Many factors have been identified besides patients' frail and diseased state including unfamiliar environment, noise, unstructured nurses' shift changes, and reduced staffing. It would be a misnomer to name it purely as a disease of evening time. Sundowning has been reported with shift changes at 3 PM also.
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