Hallucinations are a real symptom of dementia, not a sign of something else
Yes, dementia can cause hallucinations. They happen because dementia damages the parts of the brain that process what you see, hear, smell, taste, and feel. A person with dementia may see people or animals that aren't there, hear voices or music, or feel sensations on their skin. These experiences feel completely real to the person having them — they are not making it up or trying to get attention.
Hallucinations are more common in some types of dementia than others. Lewy body dementia causes them in about 80 percent of people who have it. Alzheimer's disease causes them less often, usually in the middle or later stages. Vascular dementia and frontotemporal dementia can also bring hallucinations, though the pattern varies from person to person.
The hallucinations usually start small — a shadow that looks like a person, a sound that seems like footsteps — and can become more detailed over time. They often happen at certain times of day, especially in the late afternoon or evening, a pattern sometimes called "sundowning."
Key Takeaways
- Hallucinations in dementia are caused by brain damage, not by medication side effects or confusion, though those can make them worse.
- Visual hallucinations are the most common type, followed by hearing voices or sounds that aren't there.
- The person experiencing the hallucination believes it is real, so telling them "that's not real" usually makes them more upset, not less.
- A doctor should rule out other causes like infection, medication, or low blood sugar before assuming the hallucinations are from dementia alone.
- Reducing triggers like dim lighting, loud noise, and fatigue can lower how often hallucinations happen.
Why dementia causes hallucinations
The brain regions that interpret sensory information — what your eyes see, what your ears hear — start to fail in dementia. The brain may misread signals, fill in gaps with false information, or replay old memories as if they are happening right now. This is not the person's imagination or confusion. It is their brain misfiring in a specific, measurable way.
Lewy body dementia causes hallucinations more often because it involves the buildup of a protein called alpha-synuclein in the brain. This protein damages the visual processing centers specifically. People with Lewy body dementia often see detailed, vivid scenes — a person sitting in a chair, animals moving around the room — rather than vague shadows.
In Alzheimer's disease, hallucinations usually come later, as more of the brain is affected. They tend to be less detailed and more tied to the person's past — seeing a deceased parent, hearing a familiar voice, or feeling a familiar touch.
The difference between hallucinations and delusions
A hallucination is something the person sees, hears, or feels that is not there. A delusion is a false belief that the person holds even when shown evidence it is not true. Dementia can cause both, and they often happen together.
For example, a person might hallucinate seeing a stranger in the room (hallucination) and then believe that stranger is trying to steal from them (delusion). Or they might hear voices (hallucination) and believe those voices belong to someone specific who is trying to harm them (delusion).
Understanding the difference matters because the two sometimes need different responses. A hallucination may fade if you change the lighting or reduce noise. A delusion usually requires a different approach — validating the person's feelings while gently redirecting their attention, rather than arguing about what is real.
When to see a doctor about hallucinations
A doctor should always evaluate new hallucinations, even if the person already has a dementia diagnosis. Hallucinations can be caused by things other than dementia alone — a urinary tract infection, medication side effects, low blood sugar, dehydration, or sleep deprivation can all trigger them. Treating the underlying cause may stop the hallucinations without changing dementia medication.
Tell the doctor when the hallucinations started, what the person sees or hears, how often they happen, and whether anything seems to trigger them. Write down the times of day they occur and what the person was doing before they started. This information helps the doctor figure out whether the hallucinations are from dementia, from something else, or from a combination.
The doctor will also review all medications the person is taking. Some blood pressure drugs, sleep aids, pain relievers, and other medications can cause hallucinations as a side effect. Changing the dose or switching to a different drug may help.
How to respond when someone is having a hallucination
The most important thing to remember is that the hallucination feels real to the person experiencing it. Telling them "that's not real" or "you're imagining things" usually makes them more upset and more convinced you don't believe them. They may become angry, scared, or withdrawn.
Instead, stay calm and focus on the person's feelings, not on whether the hallucination is real. If they are scared, comfort them. If they are confused, speak in a slow, gentle voice and use straightforward words. You might say, "I see you're frightened. I'm here with you, and you're safe," rather than arguing about what they see.
Sometimes redirecting attention works. If the person is seeing something frightening, you might turn on more lights, move to a different room, or suggest an activity they enjoy. If they are hearing voices, soft music or a familiar voice on the phone may help.
Do not play along with the hallucination in a way that reinforces false beliefs or puts the person in danger. If they believe they need to leave the house to meet someone who is not real, you would not help them leave. But you also would not say, "That person doesn't exist." Instead, you might say, "Let's sit down and have some tea first," buying time for the hallucination to fade.
What makes hallucinations worse
Certain situations trigger or worsen hallucinations in people with dementia. Low light is one of the biggest triggers — shadows and dim corners can look like people or animals. Turning on more lights, especially in the late afternoon and evening, can help.
Noise and overstimulation also make hallucinations more likely. A busy room with many people talking, a television playing loudly, or background music can overwhelm the brain and trigger false perceptions. Creating a calm, quiet environment with fewer distractions helps some people.
Fatigue, hunger, and pain make hallucinations worse. A person who is tired or uncomfortable is more likely to misinterpret what they see and hear. Making sure the person gets enough sleep, eats regular meals, and takes pain medication as prescribed can reduce hallucinations.
Certain medications can also trigger or worsen hallucinations. If hallucinations start or get worse after a new medication is added, tell the doctor right away. Do not stop the medication on your own, but the doctor may be able to adjust the dose or switch to something else.
Medications that may help with dementia hallucinations
If hallucinations are severe, frightening, or interfering with daily life, a doctor may prescribe medication to reduce them. The choice depends on the type of dementia and what other symptoms the person has.
For Lewy body dementia, doctors often avoid antipsychotic medications because they can cause serious side effects in this group. Instead, they may try other drugs that affect how the brain processes dopamine or serotonin. Cholinesterase inhibitors — medications already used to slow cognitive decline in some dementias — sometimes help with hallucinations too.
For Alzheimer's disease, antipsychotics are used more often, but only when hallucinations are severe and other approaches have not worked. These medications carry risks, especially in older adults, so the doctor will weigh the benefits against the risks.
Any medication for hallucinations should be started at a low dose and increased slowly. The doctor will watch for side effects and check whether the medication is actually helping. Regular follow-up visits are important to make sure the medication is still the right choice.
Frequently Asked Questions
Can hallucinations from dementia be prevented?
You cannot prevent hallucinations entirely if they are caused by dementia, but you can reduce how often they happen and how severe they are. Keeping the environment well-lit, calm, and familiar; making sure the person sleeps well and eats regularly; and treating pain or discomfort all help. Addressing other medical problems like infections or medication side effects also matters.
Do hallucinations mean the dementia is getting worse?
Hallucinations can appear at any stage of dementia, so they are not always a sign that things are getting worse. However, they do become more common as dementia progresses. If hallucinations suddenly start or get much worse, that can signal a change in the person's condition, so tell the doctor.
Will the person remember the hallucination afterward?
Some people remember hallucinations vividly after they pass, while others have no memory of them at all. Memory loss is part of dementia, so the person may forget the hallucination within minutes or hours. This can actually be a relief — they may not carry fear or distress from the experience into the next day.
Is it safe to leave someone alone if they are having hallucinations?
It depends on what the person is experiencing and how they are reacting. If they are calm and the hallucination is not causing them to wander or try to leave the house, brief periods alone may be fine. If they are frightened, agitated, or trying to act on the hallucination, they should not be left unsupervised. Talk to the doctor about what is safe for your specific situation.
Can I catch dementia hallucinations from someone else?
No. Hallucinations are a symptom of brain damage in that person — they are not contagious and cannot spread to family members or caregivers. However, living with someone who has hallucinations can be stressful for you, so it is important to take care of your own mental health and reach out for support.