Hallucinations, delusions and paranoia

A person living with dementia may see a child in an empty chair. They may hear voices when no one is there. Or they may become sure that a neighbor is stealing from them. These experiences feel completely real to the person, even when they are not.^1,2

These changes are caused by the disease, not by stubbornness or bad character. With a calm response, a check for medical causes and a few changes at home, many episodes become less frequent or less upsetting. This page explains what is happening, how to respond, what is different in Lewy body dementia, and when to get help.

What these words mean

Doctors group these experiences under the word psychosis (losing touch with what is real). In dementia, it usually shows up in three ways.

Sources for the table: Alzheimer's Association, the National Institute on Aging and the Lewy Body Dementia Association.^2,3,5

Some people believe a loved one who died is still alive. Others think strangers are living in the house.⁵ A special type is Capgras syndrome, when the person believes a familiar person has been replaced by a look-alike impostor. It is one of the false beliefs seen in Lewy body dementia.^5,8

How common is this?

Psychosis is common in dementia. A 2023 review of many studies found psychotic symptoms in about one-third to nearly two-thirds of people with dementia (34% to 63%).⁴ It was more common in Alzheimer's disease and dementia with Lewy bodies than in other types.⁴

In Alzheimer's disease, hallucinations usually appear in the later stages.¹ Delusions tend to show up in the middle to late stages.² In Lewy body dementia, visual hallucinations affect up to 8 in 10 people.⁶

Why it happens

Dementia damages the parts of the brain that make sense of what we see, hear and remember.³ When memory fails, the brain tries to fill in the gaps. For example, a person who cannot remember hiding their purse may decide someone took it.³

Other things can cause or worsen these symptoms:^1,7

• Infections, such as bladder or kidney infections
• Dehydration or strong pain
• Constipation or pressure sores
• Poor eyesight or hearing
• Medicines, including some sleep aids, bladder medicines, Parkinson's medicines and benzodiazepines (calming medicines such as lorazepam). See medicines that can worsen memory.
• Alcohol or drug use
• Dim light, shadows, mirrors and loud or violent TV shows^1,3

A person who suddenly becomes confused or starts seeing things over hours or days may have delirium (sudden confusion caused by an illness or medicine). This is a medical problem that needs prompt care. See hospital stays and emergency rooms.

How to respond in the moment

First, ask yourself: is this causing a problem? If the person is calmly chatting with a "visitor" and is not upset, you may not need to do anything.¹ If they are frightened or unsafe, act quickly and calmly.

1. Stay calm. Speak slowly in a low, gentle voice. Your calm helps theirs.
2. Do not argue or try to prove them wrong. Logic does not reach a brain that is misreading the world. It often makes the person more upset and more certain.^2,8
3. Respond to the feeling. Say what you see: "That sounds scary" or "You seem worried." A gentle touch or pat on the hand may help.^1,3
4. Tell the truth gently, without denying their experience. If asked, you might say, "I know you see something. I don't see it, but I'm right here with you."¹
5. Offer reassurance. "You are safe. I will stay with you."³
6. Change the focus. Suggest a walk, a snack, music, photos or a simple chore. Moving to a bright room with other people often helps a frightening hallucination fade.^1,3
7. Keep answers short. Long explanations are hard to follow.²

For more on calm words and body language, see talking with someone who has dementia.

Changes at home that help

Keep a simple log of when episodes happen, what came before and what helped. Patterns often appear. Our behavior diary makes this easier, and it helps the doctor too.

When they accuse you of stealing

Accusations of theft are one of the most painful things caregivers face. They often come from memory loss. The person puts something away, forgets, and the only explanation that makes sense to them is that someone took it.³ Sometimes the person also feels a deep sense of loss, and blaming someone is a way to explain it.³

What can help:

• Try not to take it personally. The disease is speaking, not the person you know.^2,3
• Listen and reassure. Do not defend yourself at length. Say, "Let's look for it together."²
• Keep spares. If the same item keeps going missing, buy two of the same wallet, glasses case or purse.²
• Learn the hiding places. Many people tuck things in the same few spots, like drawers, shoes, coat pockets or under the mattress. Check wastebaskets before you empty them.
• Tell others. Let family, friends and helpers know these accusations come from the illness.³
• Lock up what matters. Keep important papers, cash and jewelry in a safe place.

Lewy body dementia: what is different

Hallucinations are a core sign of Lewy body dementia. This includes dementia with Lewy bodies and Parkinson's disease dementia. In Lewy body dementia, visual hallucinations occur in up to 80% of people.⁶ They are often clear and detailed, such as people or animals. Hearing, smell or touch can be involved too.⁵

Medicine sensitivity is a serious concern. An estimated 25% to 50% of people with Lewy body dementia who take antipsychotic medicines at usual doses have a severe reaction.⁶ Reactions can include worse thinking, heavy sleepiness, stiffness and a rare reaction with high fever and rigid muscles that can be fatal.^6,7 Older antipsychotics such as haloperidol should be avoided.^6,7 This matters most in the emergency room, where these drugs are sometimes given quickly for agitation.

What families can do:

• Make sure every doctor, hospital and pharmacy knows the diagnosis. Keep a note in the person's wallet and in the medicine list.
• Ask before any new calming medicine in the hospital or ER: "Is this safe in Lewy body dementia?"
• Ask about cholinesterase inhibitors. These memory medicines may lessen hallucinations in Lewy body dementia, though the effect takes time.⁷ See donepezil, rivastigmine and galantamine.
• Ask whether Parkinson's medicines play a role. Medicines for movement can trigger hallucinations. Changes need a careful balance and must be made by the doctor.⁷
• Try the Capgras tips if the person thinks you are an impostor. Call out or phone before you walk in, since hearing your voice may not trigger the false belief the way seeing you does. If it happens, step out and come back in a few minutes.⁸

The Lewy Body Dementia Association runs a help line, the Lewy Line, at 1-800-539-9767.⁵

What about medicines?

Non-drug approaches come first.^1,2 If hallucinations are mild and not distressing, treatment may not be needed at all.⁷

Medicine may be considered when symptoms are severe, frightening, or put anyone in danger, and other steps have not worked.^1,2 Antipsychotic medicines can help some people. But they carry real risks. These medicines carry an FDA boxed warning (the strongest warning) about a higher risk of death in older adults with dementia-related psychosis.⁹

In 17 studies, older people with dementia who took these medicines had 1.6 to 1.7 times the risk of death of those taking a placebo (a look-alike pill with no medicine). Over about 10 weeks, roughly 4.5 in 100 people on the drug died, compared with 2.6 in 100 on placebo. Most deaths were from heart problems or infections like pneumonia.⁹ The Alzheimer's Association also notes a higher risk of stroke.¹

Pimavanserin (Nuplazid) is FDA-approved for hallucinations and delusions linked to Parkinson's disease psychosis. As of October 2026, its label says it is not approved for other dementia-related psychosis.⁹ If a doctor suggests a medicine, ask:

• What is the goal, and how will we know it is working?
• What side effects should we watch for, such as falls, sleepiness or stiffness?
• How long will the person take it, and when will we check whether it is still needed?

Doctors usually start low and go slow. Talk with the doctor or pharmacist before changing or stopping anything. For more, see medicines for agitation and behavior.

When to get help

Call the doctor the same day if:

• Hallucinations or delusions start suddenly or get much worse over a few days. This may be delirium, an infection or a medicine reaction.¹
• The person also has fever, new trouble walking, much more sleepiness or confusion, or signs of pain.
• The person stops eating, drinking or taking medicine because they think it is poisoned.
• A person with Lewy body dementia got a new antipsychotic or calming medicine and is now stiffer, sleepier or more confused.⁶

Book a regular visit if episodes are frequent or distressing, even if they are not dangerous.² Bring your log and a full list of medicines, including over-the-counter ones.³

Take care of yourself, too. Being accused or seeing a loved one frightened is exhausting. Talk to other caregivers, take breaks and ask for help. The Alzheimer's Association Helpline is 1-800-272-3900.³ See caregiver stress and burnout. If you feel overwhelmed or hopeless, call or text 988 any time.

Education only. This page is general information written from the sources listed. It is not medical, legal or financial advice and does not replace a doctor, therapist or lawyer who knows your situation. How we write and check pages.