Understanding dementia

Illustration: abstract shapes floating around a woman who is reading a book

Dementia can be more than memory loss

Dementia affects around 7.9 million people in the United States. It is not a single disease, but a general term for a range of conditions, including Alzheimer's disease. These conditions are caused when healthy brain cells are damaged and lose connections with each other.

As these changes in the brain occur, they may worsen over time. They may lead to problems with memory, thinking, and behavior, which can affect activities of daily life.

These changes in the brain can also cause hallucinations and delusions. In the United States, about 1 in 3 people with dementia may experience these symptoms. They can create unique challenges for you and your loved one. So it is important to learn more about them.

What are dementia-related hallucinations and delusions?

Hallucinations are when someone sees, hears, smells, tastes, or feels things that are not there.

Delusions are when someone believes things that are not true, such as thinking someone is stealing from them.

Learning about these symptoms is the first step toward getting help.

Learn more about these symptoms
Eyeball icon represents the visual hallucination of seeing people or things that aren’t there

My mother sees a little boy in the house. I try to tell her he isn’t real but she doesn’t believe me. She’s afraid of him.* Linda

Masked bandit icon represents the delusion of believing someone is trying to steal or hide things from you

She calls me all upset, claiming I’ve stolen her money or her jewelry or that I’m hiding things from her.* Maureen

*These are real caregiver examples. Individual experiences may vary.

Illustration: scattered numbers and blurred circles that represent mild cognitive impairment (MCI) symptoms

Mild cognitive impairment

Some people may not have dementia at first. They may be told that they have mild cognitive impairment (MCI), a condition that causes small but noticeable changes in brain function.

These changes can include problems with thinking, judgment, memory, and language. But they may not affect activities of daily life the way dementia symptoms do.

People with MCI may be more likely to develop a type of dementia over time.

What are the most common types of dementia?

There is no single disease called dementia. There are several kinds of dementia. People may have hallucinations and delusions with many of them.

Some of the most common forms of dementia are:

Accordion icon Alzheimer’s Disease Dementia

Alzheimer's disease is the most common form of dementia. It causes changes in the brain, which at first can lead to mild memory loss. People may find it difficult to remember recent conversations, names, or events. As Alzheimer's disease progresses, people may become disoriented, and they may have a hard time speaking. About 1 in 3 people with Alzheimer's disease may experience hallucinations and delusions.

The second most common type of dementia is vascular dementia. It is caused by damage in the blood vessels that leads to bleeding in the brain. Symptoms may include problems with decision-making, difficulty with movement, and poor balance. Hallucinations and delusions may also occur in people with vascular dementia.

Another type of dementia is dementia with Lewy bodies. Lewy bodies are tiny proteins that form in the brain. They can cause changes in the brain that lead to a range of symptoms. Symptoms can include problems with memory, thinking, sleep, and movement. Around 3 out of 4 people with this type of dementia may experience hallucinations.

Parkinson's disease dementia often comes with Lewy bodies. Lewy bodies are tiny proteins that form in the brain and lead to a range of symptoms. At first, this condition may affect movement. This can lead to slow movement, tremors, muscle stiffness, and difficulty starting movement. Over time, people may experience changes in memory and behavior too. About 50% of people with Parkinson's disease dementia have hallucinations and delusions.

Frontotemporal dementia leads to changes in the front and sides of the brain. At first, symptoms can include changes in character and behavior, as well as difficulty with language. As the disease gets worse, memory problems may develop too. Hallucinations and delusions may also occur in people with frontotemporal dementia.

Contact an advocacy organization

Are you living with or caring for someone with dementia? Reach out to an advocacy organization to connect with others who know what you're going through. They can also provide resources that may help you handle everyday situations.

Lewy Body Dementia Association
The Association for Frontotemporal Degeneration
Directional signs icon represents learning about dementia-related hallucinations and delusions, which vary from person to person

Hallucinations and delusions can vary from person to person. Learn about these common signs.

Speech bubbles icon represents discussing dementia-related hallucinations and delusions with your doctor

Ready to speak to your doctor?
A doctor discussion guide can help you prepare for that conversation.