Nocturnal delirium (or sundowning) is a phenomenon experienced by elderly individuals with dementia that causes increased delirium and agitation. One theory about the phenomenon is that it is related to sensory input changes due to decreased light associated with late afternoon/evening time. It is recommended to provide good lighting and sensory input during the daytime hours. Sleep and circadian rhythm alterations contribute to sundowning; an afternoon nap may make the symptoms worse. It might be necessary to make changes to the medication regimen, but providing good sensory input is a less invasive intervention. Telling the caregiver about the patient’s possibility of an arthritic disease is less helpful than providing a possible solution.