Delusions and Alzheimer's Disease

Get an explanation of delusions and how to help the person with Alzheimer's suffering from a delusion at HealthyPlace.

Explanation of delusions and how to help the person with Alzheimer's suffering from a delusion.

Definition of delusion: Delusions are ideas that are not based on reality, but which are thought to be true by the person with Alzheimer's or dementia. Their content can often be centered on people stealing money or other possessions, or they may have fixed ideas about people intending to harm them.

A person with Alzheimer's may sometimes become rather suspicious. This is usually because of their failing memory. They may accuse someone of stealing from them when something has been mislaid, for example. However, they are often reassured when the object is found.

With some people this suspicion goes much deeper and they may develop distorted ideas about what is actually happening. The person may become convinced that other people want to harm them, for example, and no amount of evidence to the contrary will persuade them otherwise. This kind of belief is called a delusion and can be very distressing both for the person with Alzheimer's and for those who care for them.

Common delusions that people with Alzheimer's have are:

  • Their partner is being unfaithful
  • Their partner or a close relative has been replaced by an impostor who closely resembles them
  • Their home is not their own and they do not recognize it
  • Their food is being poisoned
  • Their neighbors are spying on them

A person with Alzheimer's has these odd ideas because of the changes that are occurring in their brain. However, sometimes these ideas may be created by hallucinations.

There is little point in arguing with the person as only cause further distress to both of you.

Tips for helping the Alzheimer's patient with delusions

  • Try to reassure the person that you are on their side and want to help them.
  • Distract them with other activities.
  • Ask for advice from your doctor.
  • Medication can sometimes be helpful, particularly if the person is becoming aggressive. This type of medication needs to be reviewed regularly. Ask your doctor.

Explaining behavior

It is important to explain any unusual beliefs or behavior to anyone who comes into contact with the person with Alzheimer's. If they understand the situation, they will be more able to reassure or distract the person as appropriate.


  • Alzheimer's Australia
  • Alzheimer's Society - UK - Carer's Advice Sheet 520, Jan. 2000

APA Reference
Staff, H. (2021, December 20). Delusions and Alzheimer's Disease, HealthyPlace. Retrieved on 2024, May 30 from

Last Updated: January 5, 2022

Medically reviewed by Harry Croft, MD

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