Hallucinations in dementia patients

Naomi Carr
Author: Naomi Carr Medical Reviewer: Morgan Blair Last updated:

There are several types of dementia. Each can cause slightly different symptoms, including symptoms of psychosis, such as hallucinations and delusions. Hallucinations can be very distressing or frightening but can be managed with both non-drug approaches and certain types of medications.

Why does dementia cause hallucinations?

Dementia can cause many different symptoms, including impairments in memory, cognition, and mobility. It is also common for people with dementia to experience what are referred to as behavioral and psychological symptoms of dementia (BPSD). Symptoms of BPSD include irritability, aggression, depression, anxiety, and psychosis [1].

Psychosis can cause the presence of hallucinations, delusions, and paranoia, which are commonly observed symptoms in those with certain types of dementia or in the later stages of dementia [2].

Hallucinations can involve any of the five senses. The most common types of hallucinations are visual (seeing things that aren’t there) and auditory (hearing things that aren’t there). Other types of hallucinations are gustatory (taste), olfactory (smell), and tactile (feelings and sensations) [3].

Visual hallucinations are most common in dementia with Lewy bodies and are believed to occur in over half of those with this diagnosis. Hallucinations also occur in Parkinson’s disease dementia, Alzheimer’s disease, and vascular dementia [3][4].

Dementia is caused by changes and damage in the brain. These changes are often because of a buildup of protein plaques in certain areas, which leads to the occurrence of dementia symptoms. As most types of dementia are degenerative, hallucinations become more common in the later stages, as the condition worsens [5][6].

Lewy bodies and other protein deposits in the brain impact the production and function of neurotransmitters. Research suggests that an imbalance of the neurotransmitters, serotonin, dopamine, and acetylcholine, greatly contribute to the occurrence of hallucinations [6][7].

Hallucinations can also occur in those with dementia as a result of other causes, such as infections and illnesses that cause delirium, or as a side effect of certain medications. In these circumstances, the presence of hallucinations can be reduced by medical intervention [3].

Treatment for dementia hallucination

Initially, changes in behavior and perceptions should aim to be managed without the use of medications. Hallucinations could be reduced or prevented by ensuring that physical health is looked after, by attending regular checkups and utilizing equipment such as glasses and hearing aids, as well as providing social and physical activity to stimulate the brain and prevent stress or frustration [8].

If hallucinations persist or worsen, medications might be required, such as:

Anti-dementia medications

Often, upon receiving a diagnosis of dementia, individuals will be prescribed a medication called an acetylcholinesterase inhibitor, such as rivastigmine or donepezil, which can help to reduce the impact of dementia symptoms. These medications have also been found to be helpful in reducing the occurrence of hallucinations, particularly in those with Lewy body dementia [1][9].

Similarly, a medication called memantine is often prescribed in the treatment of dementia, usually alongside an acetylcholinesterase inhibitor, to aid in reducing dementia symptoms. Memantine can also help to reduce the symptoms of dementia psychosis, such as hallucinations [4][9].


Antidepressant medications, in particular selective serotonin reuptake inhibitors (SSRIs) such as citalopram and sertraline, have been found to be useful in the treatment of dementia psychosis, such as helping to reduce hallucinations. Furthermore, they increase serotonin levels so can also positively impact mood [1][9].

Research has also shown that citalopram can reduce the build up of plaques in the brain in those with Alzheimer’s, thus potentially slowing degenerative effects [1].


Antipsychotic medications are effective at reducing symptoms of psychosis but have been found to significantly increase the risk of side effects in older adults, such as impacting cognition, mobility, heart function, and gastrointestinal function, as well as increasing the risk of death [9].

As such, the US Food and Drug Administration (FDA) issued a warning against the use of antipsychotic medications in the treatment of dementia. However, some antipsychotics, such as olanzapine and risperidone, are still used off-label in the treatment of dementia psychosis, when it is deemed necessary by a medical professional on an individually assessed basis [1].

A newer antipsychotic medication, pimavanserin, considered to be somewhat unique in this class of medications, has recently been approved for use in the treatment of Parkinson’s disease dementia. It has been found to be effective in reducing symptoms of psychosis in Parkinson’s and in other types of dementia, while being far less likely to cause dangerous or unpleasant side effects [1][4][6].

How to tell is someone is hallucinating

Someone who is hallucinating may show emotional or physical responses to the things they are experiencing. For example, they may speak in response to a voice they have heard or directed at a figure that they can see, or touch or scratch their skin where they have felt something, which could indicate the presence of hallucinations [10].

Similarly, they may become frightened or confused, making reference to scary or unpleasant noises, sensations, people, or scents that cannot be noticed by others [3][10].

Hallucinations can affect any of the senses. They may be caused by physical impairments in sensory perceptions, such as poor eyesight, hearing, or dental issues. As such, it may be useful to check if any of these impairments are present, or if hearing aids, dentures, or glasses are being appropriately used, to help determine whether it is a hallucination or misperception being experienced [3][10].

How to help someone with dementia who is experiencing hallucinations

Hallucinations occurring in the context of dementia may be caused or worsened by several factors, so there are various ways in which to help alleviate the impact or distress that they can cause. For example [2][3][10]:

  • Determine whether the individual is experiencing a physical complication, such as dehydration, infection, or gastrointestinal issues, that could be causing delirium, thereby contributing to the presence of hallucinations.
  • Similarly, ensure that their eyesight and hearing is not being impaired, either by poorly working equipment such as hearing aids or by lighting and noises in the environment.
  • Provide distractions, company, and conversation, or change their environment, to help them feel comfortable and engaged, thereby potentially helping to reduce or distract from hallucinations.
  • Provide reassurance when they are experiencing a hallucination, particularly if they are frightened, by letting them know you are there to help and protect them.
  • Don’t tell them that they are wrong or just imagining the experience, as this can cause confusion and distress, but also don’t tell them that you can see/hear/feel the same thing if it is not real. Instead ask them to explain what they are experiencing.
  • Ensure that there is nothing available to them that they could use to harm themselves or others, particularly if they are becoming distressed by their hallucination and could react dangerously.
  • Seek professional help, particularly if the hallucinations persist or worsen. An assessment can also help to determine if hallucinations are caused by underlying physical health concerns or medications, which can be treated or changed.
  1. Marcinkowska, M., Śniecikowska, J., Fajkis, N., Paśko, P., Franczyk, W., & Kołaczkowski, M. (2020). Management of Dementia-Related Psychosis, Agitation and Aggression: A Review of the Pharmacology and Clinical Effects of Potential Drug Candidates. CNS Drugs, 34(3), 243–268. Retrieved from https://doi.org/10.1007/s40263-020-00707-7
  2. National Institute on Aging. (Reviewed 2017). Alzheimer’s and Hallucinations, Delusions, and Paranoia. NIA. Retrieved from https://www.nia.nih.gov/health/alzheimers-and-hallucinations-delusions-and-paranoia
  3. Alzheimer’s Society. (Reviewed 2021). Hallucinations and Dementia. Alzheimer’s Society. Retrieved from https://www.alzheimers.org.uk/about-dementia/symptoms-and-diagnosis/hallucinations
  4. O’Brien, J., Taylor, J. P., Ballard, C., Barker, R. A., Bradley, C., Burns, A., Collerton, D., Dave, S., Dudley, R., Francis, P., Gibbons, A., Harris, K., Lawrence, V., Leroi, I., McKeith, I., Michaelides, M., Naik, C., O’Callaghan, C., Olsen, K., & Onofrj, M. (2020). Visual hallucinations in neurological and ophthalmological disease: pathophysiology and management. Journal of Neurology, Neurosurgery & Psychiatry, 91(5), 512–519. https://doi.org/10.1136/jnnp-2019-322702
  5. El Haj, M., Roche, J., Jardri, R., Kapogiannis, D., Gallouj, K., & Antoine, P. (2017). Clinical and Neurocognitive Aspects of Hallucinations in Alzheimer’s Disease. Neuroscience and Biobehavioral Reviews, 83, 713–720. Retrieved from https://doi.org/10.1016/j.neubiorev.2017.02.021
  6. Cummings, J.L., Devanand, D.P., & Stahl, S.M. (2020). Dementia-Related Psychosis and the Potential Role for Pimavanserin. CNS Spectrums, 27(1), 7-15. Retrieved from https://doi.org/10.1017/S1092852920001765
  7. National Library of Medicine. (Updated 2021). Dementia with Lewy Bodies. MedlinePlus. Retrieved from https://medlineplus.gov/genetics/condition/dementia-with-lewy-bodies/#causes
  8. Alzheimer’s Society. (Reviewed 2021). Non-Drug Approaches to Changes in Mood and Behavior. Alzheimer’s Society. Retrieved from https://www.alzheimers.org.uk/about-dementia/treatments/dementia-drugs/non-drug-approaches-changes-mood-and-behaviour
  9. Alzheimer’s Society. (Reviewed 2021). Antipsychotics and Other Drug Approaches in Dementia Care. Alzheimer’s Society. Retrieved from https://www.alzheimers.org.uk/about-dementia/treatments/drugs/antipsychotic-drugs
  10. Dementia UK. (2023). Changes in Perception and Hallucinations in Dementia. Dementia UK. Retrieved from https://www.dementiauk.org/get-support/understanding-changes-in-dementia/changes-in-perception-and-hallucinations-in-dementia/
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Naomi Carr
Author Naomi Carr Writer

Naomi Carr is a writer with a background in English Literature from Oxford Brookes University.

Published: May 16th 2023, Last edited: Nov 10th 2023

Morgan Blair
Medical Reviewer Morgan Blair MA, LPCC

Morgan Blair is a licensed therapist, writer and medical reviewer, holding a master’s degree in clinical mental health counseling from Northwestern University.

Content reviewed by a medical professional. Last reviewed: May 16th 2023