An angry, older woman yells at a younger woman about a necklace that she can't find (but is actually hanging around her neck).

How Are Illusions, Delusions, and Paranoia Related to Alzheimer's Disease?

Last updated: July 2022

Understanding symptoms of Alzheimer's disease and related dementia is hard because symptoms vary so much between people and as they change over the course of the disease—and even from day-to-day! This is, of course, difficult for caregivers as well as the person living with the symptoms themselves.

A family member and I had a conversation the other day and she posed the question about a specific symptom: Paranoia. Of course, like many people who have an older relative with Alzheimer's disease, we second guess what could be a manifestation of the disease regularly!

Paranoia, delusions, and illusions

To be more accurate, delusions are the specific Alzheimer's disease symptom that leads to paranoia. The Alzheimer's Association explains delusions as "firmly held beliefs in things that are not real."1

Delusions result from Alzheimer's symptoms of confusion and memory loss but can also be caused by another medical condition such as an infection, so it is important to rule out medical causes.2

Common delusions are that family members or friends may be stealing things (because they cannot remember where they have put the item or may not "see it" even though it is there—more on illusions in a moment), that they are being followed, that someone is in their home, or that a loved one is an "impostor."2

It's also noted that delusions cannot be reasoned with, making it even more difficult to help the person experiencing them cope.3

Illusions are a misinterpretation of visual stimulus that is not interpreted correctly by the brain as what it is. These are unlike hallucinations in which a person sees or hears people are things that are not present.1,4

Behavior changes may occur as a result of the suspicious delusions the person is experiencing: hiding things, accusations and suspiciousness, agitation (that may lead to aggression), and being resistant to all or some people providing care or entering their space.2

Causes of Alzheimer's-related delusions

Like other symptoms of Alzheimer's, delusions are caused by the degeneration of the brain's cells and tissues. Accusations are not easy to deal with, especially if you are accused. Still, it is important to remember it is a symptom, even if it feels like a personal attack—though this does not always make it easier to deal with. Take the example of "missing" items, we know that the item is not really missing. Still, misplaced, hidden, or simply the person cannot “see” where it is—even if it is — and Alzheimer's disease directly causes those things.2

How to manage delusions

Most often, calmly acknowledging the problem as true and then distracting, generally from rumination in conversation, is something we find useful. Other suggestions might include determining causes or triggers for the situation or response, offering to help “look for” items that are “missing,” and doing what you can to prevent the problem from arising.4

This includes helping to maintain routines, knowing places items may be hidden by the person and forgotten, having duplicate items (if "missing" items are consistent and not random—we have experienced the latter!), and ensuring adequate lighting to reduce eye - brain shadow related trickery can help.4

Cross off other possible causes

It's important to ensure a physical problem with vision or hearing, or other psychiatric disorders, are not causing the problem, too. Finally, the Alzheimer's Society of Cornwall and District in Ontario notes that in some cases, you may truly need to investigate a person's suspicions because, of course, they may be true and not a manifestation of Alzheimer disease!4

Have you dealt with paranoia, illusions, and delusions associated with Alzheimer's? What strategies have helped you cope?

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This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The AlzheimersDisease.net team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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