At certain stages of the disease, Alzheimer's sufferers may show signs of agitation, especially towards evening (sundowning). Increased agitation late in the day is a matter of fatigue, not a response to changing light. People with Alzheimer's Disease have to work hard just to perceive the environment, understand it, and respond to people in it. Any neurological disease causes severe fatigue.

Unfortunately, late in the day is a time of fatigue for carers as well. This is also often a busy time when a carer would normally have many other tasks to perform - organise the family and dinner. If sundowning is a problem, organisation of meals etc may have to be done earlier in the day. Rest periods, organisation and routine are perhaps the most useful responses to this phenomenon for the welfare of both the person and the carer.

As with most disturbing behaviours, this may be a phase of the disease, but there are other factors that can contribute to the problem including

• inability to perform a task
• overtiredness and/or sleep deprivation
• pain, fever, illness or constipation
• side effects of medications
• impaired vision or hearing leading to misinterpretation of sights and sounds or hallucinations
• sensory overload - too much noise and activity
• unfamiliar people, places or sounds leading to feelings of insecurity
• change in routine
• being asked to respond to too many questions or instructions at once
• response to stress or irritability of others or by arguments between others
• being scolded or contradicted
• feeling insulted by tone and manner of others or by being treated like a child.