Sadness, agitation, fear, as well as other mood and behavior changes that occur just before dark are called Sundowner's Syndrome, or "sundowning." Caregivers might notice that their parent who has Alzheimer's disease or dementia becomes more agitated at twilight.
Behaviors and emotional issues associated with Sundowners Syndrome include:
People with Sundowner's Syndrome may also "shadow" you, following you around and doing everything you do. They might ask you questions over and over or interrupt you when you're speaking to someone else. They may lose their full language abilities, and abstract thoughts may become especially difficult for them to comprehend.
Doctors and researchers aren't sure that causes sundowning, but the theory is that the symptoms have something to do with the onset of darkness.
Some medical professionals believe that the syndrome is an accumulation of all of the sensory stimulation from the day that starts to overwhelm and cause stress. Others speculate that it is caused by hormonal imbalances that occur at night. Another theory follows that the onset of symptoms at night is simply due to fatigue; while some believe it has to do with the anxiety caused by the inability to see as well in the dark.