Memory & Dementia
What Is Lewy Body Dementia?
Amarish Dave, DO explains Lewy body dementia, including changes in thinking and alertness, visual hallucinations, movement symptoms, and acting out dreams.
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Why Do People With Dementia Have Hallucinations?
Hallucinations are experiences in which someone sees, hears, or otherwise senses something that is not actually present. They can occur in dementia, but a new or sudden change should not automatically be assumed to be dementia progression.
Written and medically reviewed by Amarish Dave, DO, board-certified neurologist. This page is educational and does not replace an individual medical evaluation.
What can a dementia hallucination look like?
Hallucinations can be visual, auditory, or involve another sense. A person may:
- See people who are not there
- See animals, children or objects
- Believe someone is standing in the room
- Hear voices or sounds
- Misinterpret shadows, reflections or objects
Some hallucinations are frightening, while others may not bother the person at all.
Why does dementia cause hallucinations?
Dementia can disrupt the brain networks responsible for processing and interpreting sensory information. The brain normally takes information from the eyes and other senses and determines what is actually happening in the environment.
When these brain networks are affected by disease, the brain can sometimes generate or incorrectly interpret perceptions. That experience can feel very real to the person, even when no one else sees or hears it.
Lewy body dementia and hallucinations
Recurrent, well-formed visual hallucinations are one of the characteristic clinical features of dementia with Lewy bodies. Someone may see detailed people or animals that are not actually present.
Hallucinations alone do not prove a specific diagnosis, but they are an important clue when considered together with fluctuating attention, movement changes, sleep symptoms and the overall history. Learn more about Lewy body dementia.
A new hallucination is not always from dementia
If someone with dementia suddenly begins hallucinating, or if hallucinations become dramatically worse, do not automatically assume the dementia has progressed. A sudden change in behavior, awareness or mental status should be medically evaluated.
A new hallucination is not always from dementia
Potential contributing factors can include:
- Infection or other acute illness
- Delirium
- Medication effects
- Dehydration
- Metabolic abnormalities
- Sleep disruption
- Vision or hearing impairment
A careful dementia evaluation and medical review can help separate a longer-term cognitive condition from sudden delirium or another treatable problem. Learn what happens during a dementia evaluation and what tests are ordered when evaluating for dementia.
What should a caregiver do during a hallucination?
Arguing with the person or repeatedly insisting that what they see is not real may increase distress. It is usually more helpful to focus on safety, reassurance and the level of distress.
- Stay calm
- Reassure the person that they are safe
- Determine whether the hallucination is actually upsetting them
- Reduce confusing shadows, reflections or environmental triggers
- Redirect attention when appropriate
- Look for recent medication changes or signs of illness
- Contact the person's healthcare professional if hallucinations are new, worsening or causing safety concerns
Caregivers may also find practical education through the guide to managing agitation in dementia, plus additional caregiver resources in the Illinois Dementia Guide.
Do all hallucinations need medication?
No. If a hallucination is not frightening or creating a safety problem, medication may not always be necessary. Treatment should first consider possible triggers and the underlying cause.
When medication is being considered, treatment must be individualized. Some people with Lewy body dementia can be particularly sensitive to certain antipsychotic medications, making medical supervision especially important. Learn more about how dementia is treated and lifestyle and dementia.
Key takeaways
- Hallucinations are perceptions without something actually present.
- Visual hallucinations are especially associated with Lewy body dementia, but other causes are possible.
- Sudden or dramatically worse hallucinations may reflect infection, delirium, medications or another medical problem.
- Caregiver response should emphasize calm reassurance, safety and reducing triggers.
- Medication is not always needed, and medication choices require individualized medical supervision.
Continue learning about memory and dementia
Hallucinations are one part of a broader memory and behavior picture. Continue with memory loss and dementia evaluation, frontotemporal dementia, why someone with dementia can seem normal sometimes, and the Neurology Video Library. Caregivers can also review practical guidance for managing urinary incontinence in dementia and managing agitation in dementia.
Free Illinois family resource
Illinois Dementia Guide
Practical guidance for Illinois families navigating memory loss, Alzheimer's disease and other forms of dementia.
Explore information about diagnosis, treatment, caregiving, safety, planning, lifestyle and dementia resources for Illinois families.
Explore the Illinois Dementia Guide →Frequently asked questions
- Are hallucinations common in dementia?
- Hallucinations can occur in dementia, but they are not equally common in every type. They are especially associated with dementia with Lewy bodies, and they can also occur in Alzheimer's disease and other neurological or medical conditions.
- What type of dementia causes hallucinations?
- Recurrent, well-formed visual hallucinations are a characteristic clinical feature of dementia with Lewy bodies. Hallucinations can also occur in Alzheimer's disease, Parkinson's disease dementia, delirium, medication reactions, infections and other conditions.
- Why does someone with dementia see people who aren't there?
- Dementia can disrupt brain networks that process visual and sensory information. The brain may misinterpret shadows, reflections or objects, or it may generate a perception that feels real even though nothing is actually present.
- Should you tell someone with dementia that their hallucination isn't real?
- Repeatedly arguing that a hallucination is not real can increase distress. It is often better to stay calm, reassure the person that they are safe, check whether the experience is upsetting, reduce triggers and redirect attention when appropriate.
- Can medications cause hallucinations in someone with dementia?
- Yes. Some medications can cause or worsen hallucinations, confusion or delirium, especially in older adults or people with dementia. New or worsening hallucinations should prompt a review of medications with a healthcare professional.
- Can an infection suddenly cause hallucinations?
- Yes. Infection, dehydration, metabolic problems and other acute illnesses can cause delirium, which may include hallucinations or sudden confusion. A sudden change in mental status should be medically evaluated.
- When should hallucinations in dementia be medically evaluated?
- Medical evaluation is important when hallucinations are new, suddenly worse, frightening, associated with confusion or decreased alertness, linked with fever or illness, connected to a medication change, or creating safety concerns.
- Are hallucinations an early sign of Lewy body dementia?
- They can be. Recurrent, well-formed visual hallucinations are one of the characteristic features clinicians consider when evaluating for dementia with Lewy bodies, especially when combined with fluctuating alertness, movement changes or REM sleep behavior disorder.
Related dementia videos
More medically reviewed memory and dementia videos appear here automatically as they are published.
Memory & Dementia
How to Manage Urinary Incontinence in Dementia
Amarish Dave, DO shares practical, dignity-centered strategies for scheduled toileting, safer bathroom access, simpler clothing, and recognizing changes that need medical evaluation.
Watch Video
Memory & Dementia
How to Manage Agitation in Dementia
Amarish Dave, DO shares practical ways caregivers can look for triggers, reduce distress, redirect calmly, create predictable routines, and recognize sudden changes that need medical evaluation.
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Memory & Dementia
What Is the New Alzheimer's Disease Treatment?
Amarish Dave, DO explains how Leqembi and Kisunla target amyloid, who may qualify, and why biomarker confirmation, MRI monitoring, and individualized risk review matter.
Watch VideoEnjoy these short answers? Subscribe to the NeurologistCare YouTube channel for additional short videos answering common questions about memory, dementia and neurological health.
Concerned about memory loss, hallucinations or changes in thinking or behavior?
Learn more about comprehensive memory and dementia evaluation at NeurologistCare.com. In-person neurological and memory evaluations are available in Crystal Lake and Woodstock, Illinois, and Lake Geneva, Wisconsin, with telehealth available when appropriate.
Medical disclaimer
This information is for general educational purposes and is not individualized medical advice. New hallucinations or a sudden change in behavior, awareness or mental status should be medically evaluated because causes other than dementia may be responsible.
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