Alzheimer’s Disease and Hallucinations and Delusions

WebMD Medical Reference in Collaboration with the Cecil G. Sheps Center at the University of North Carolina at Chapel HillLogo for UNC Chapel Hill, Cecil G. Sheps Center
Medically Reviewed by Christopher Melinosky, MD on November 27, 2022
5 min read

Hallucinations and delusions are common in older people with Alzheimer’s disease and other types of dementia. While they’re alike in some ways, they’re not the same thing.

Hallucinations happen when someone sees, hears, feels, tastes, or smells something that isn’t really there. Someone who hallucinates might see insects crawling on their hand or hear imaginary voices. These are fairly rare with Alzheimer’s disease but are common in other types of dementia, especially Lewy body dementia.

Delusions cause someone to firmly believe in things that are clearly untrue. They might think you’re stealing their things or that there are strangers in the house. These happen in almost half of all people with any type of dementia, including Alzheimer’s disease.

Call 911 or take your loved one to an emergency room or doctor’s office right away if:

  • Hallucinations start to happen with more than one sense. For instance, they feel and hear things as well as see them.
  • Hallucinations or delusions cause them to hurt themselves or others.
  • They suddenly begin to see sparks, flashes, streaks of light, dark spots, floating spots, or spots that look like a spider web or a large fly. These could be signs of a problem with their eyes.
  • They suddenly can’t see. This could be caused by a stroke or a problem with their eyes.
  • They have severe shortness of breath or chest pain or are vomiting.

Call their doctor if:

  • You're worried they’ll hurt themselves or others.
  • The hallucinations or delusions upset them.
  • This is the first time this has happened.
  • The hallucinations or delusions start to last longer or happen more often.
  • Your loved one shows signs of delirium, like being more easily distracted or forgetful than usual, having less energy or sudden changes in personality and behavior, being strangely emotional, or rambling when they talk.


Hallucinations and delusions can be caused by many things:

  • Trouble seeing or hearing: Poor light, background noise, or poor eyesight or hearing make it hard to see and hear well. When someone is also confused because of Alzheimer’s disease, they may see or hear things that aren’t really there.
  • Changes in the brain caused by dementia
  • Illness: Fever, seizure, stroke, migraine, or infection can affect how the brain handles information from the senses.
  • Memory problems: People with dementia sometimes don’t remember things, so their mind fills the gap in their memory with a delusion that makes sense to them.
  • Medications: Many drugs (such as steroids and stimulants) can affect the brain.
  • Drug and alcohol use or withdrawal: Use or abuse of alcohol and many drugs can cause changes in how the mind works.
  • Mental Illness: If someone has a history of serious mental illness, their hallucinations or delusions may be related to it.
  • Confusion (delirium): Certain illnesses and medications sometimes make someone more confused. This can make them more likely to have hallucinations or delusions.


Treatment of hallucinations and delusions depends on their cause. If a new medical problem is the reason, that’s what should be treated.

If the hallucinations and delusions are caused by Alzheimer’s disease or another type of dementia, some medicines may help. These are called antipsychotic medications.

Most of the time, it’s best not to use drugs, because they make a fall, heart attack, or stroke more likely.

If they’re not upset about the hallucination or delusion and not likely to do something dangerous, you might not need to do anything.

If they are upset:

  • Don’t argue with them about what they see, hear, or believe.
  • Talk to them calmly to comfort them. If they’ll let you, give them a gentle touch.
  • See if you can tell what might be making them think what they do. For instance, are they looking at a specific object? Ask them to point to where they see or hear something.
  • For some people, it's best to be honest. You might say, “I know you see something, but I don’t see it.” For others, it might help to react to what they think they see or what they think is happening. For instance, if they see snakes, pretend to kill them.
  • Distract them with a favorite activity: Listen to music, draw, or look at a photo album.
  • See if you can get them come away from that place with you.
  • Change what causes them to see or hear things. For example, if they see a face in the kitchen curtains, change the curtains or take them away.


If your loved one has a hallucination or delusion, they may get agitated. This can be because they need something. Check to see if they’ve had a bowel movement in their clothes or are wet, constipated, in pain, hungry, thirsty, or tired.

Someone who’s agitated can act in many different ways. They can be irritable, anxious, and restless. They may hit, push, or scream. If you’re worried about this, take steps to protect yourself. Step back, give them space, and take away any nearby objects that could be used as a weapon.

Remember that the things your loved one believes or thinks that they see are caused by their illness. They don’t have anything to do with them personally or how they feel about you or your care. It’s very real to them, even though you can’t see or hear it.

You can do some things to help make hallucinations and delusions less likely:

  • If your loved one needs glasses, a hearing aid, or dentures, try to make sure they wear them. Check that their glasses are clean and the right ones for the distance. Make sure their hearing aid works and is turned on. Have their eyes and ears checked regularly.
  • Make sure all rooms are well-lit. Turn on lights to get rid of shadows and reflections. Shut off sounds that might confuse them, such as noise from a TV, radio, furnace, or air conditioner.
  • Keep their home and routine as close to what they’re used to as you can. Have them be with people they know as much as possible.
  • If the same thing always causes them to have problems, change it or take it away if you can.