People with advanced dementia are more likely to experience hallucinations. Auditory and visual hallucinations are the most common, but it is also possible for them to involve smell, touch, and taste.

Dementia is a general term for cognitive decline that mostly occurs in older adults. It may cause symptoms, such as memory loss, forgetfulness, and confusion, that are severe enough to affect a person’s daily life.

Read on to learn more about hallucinations and dementia, including causes and treatments.

A hallucination experienced by a person with dementia of a person walking in a field.Share on Pinterest
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Hallucinations are sensory experiences of things that do not exist. They can affect any of the senses.

According to the United Kingdom’s Alzheimer’s Society, visual hallucinations are the most common type among people with dementia.

A 2017 study suggests that hallucinations occur in 4–76% of people with Alzheimer’s disease (AD), a type of dementia.

Hallucinations may be simple or complex, ranging from seeing flashing lights to seeing people and animals.

Dementia causes progressive brain damage and can affect the regions of the brain responsible for processing the senses, including the frontal, parietal, and occipital lobes. These changes in the sensory processing areas of the brains of people with dementia are complex and may cause them to see or hear things that do not exist to others.

Hallucinations are more common in people with Lewy body dementia and Parkinson’s disease dementia, though they can also occur in other types of dementia, including AD.

Inflammatory and infectious diseases, including pneumonia, may affect cognitive function and lead to delirium, which may cause hallucinations. People should treat this as a medical emergency. Charles Bonnet syndrome can cause visual hallucinations, but these are due to failing eyesight and not dementia.

Parkinson’s disease medications frequently cause hallucinations. However, hallucinations are a rare side effect of several other medications.

According to the Alzheimer’s Society, there are different types of hallucinations, including:

  • Auditory: A person may hear sounds, including voices or footsteps, that others cannot hear.
  • Visual: A person may see people, animals, or flashing lights that do not exist.
  • Gustatory: A person may taste something that isn’t there, including a metallic taste.
  • Tactile: People may feel things that are not touching them, including a person’s touch or an insect on their skin.
  • Olfactory: A person may sense certain smells, such as smoke, food, or perfume, that do not exist.

The way a person experiences a hallucination depends on the type. During a hallucination, a person may see, hear, or smell things that do not exist. For example, a person with dementia may see people sitting in a room with them when they are alone. They may also believe they see someone they know, but that person has passed away.

Visual hallucinations are most prevalent in people with Lewy body dementia. These hallucinations involve realistic visions of people and animals. They typically occur frequently and can continue for several minutes.

Sometimes, hallucinations can be terrifying and cause intense fear. A person may experience paranoia and panic, leading to a lack of trust in their caregivers. For some people, hallucinations are enjoyable and reassuring.

Hallucinations are extremely real to the person experiencing them. Their reactions to the hallucination may depend on how the people around them react and respond.

Learn more about what happens in the brain during a hallucination.

Treatment for hallucinations may involve medications, though they are often ineffective for people with dementia.

Some antipsychotic drugs can alleviate serious and frightening hallucinations. However, these drugs may lead to undesirable and harmful side effects, and doctors usually only prescribe them if other treatments are ineffective.

Antipsychotic drugs may be especially dangerous to people with Lewy body dementia. However, anti-dementia medications may be beneficial in reducing hallucinations for people with Lewy body dementia.

To determine if someone with dementia is hallucinating, their caregivers can look for changes in their behavior. This can involve physical movements or verbalizations that are out of character or do not make sense.

These changes may include:

  • Talking when there is no one else there: A person with dementia may be conversing with someone who is not in the room.
  • Seeing people, animals, or things that are not real: They may verbalize that they can see things others in the room cannot or speak with an empty part of a room.
  • Smelling things which are not there: A person may panic if they smell smoke when no source of that smell is present.
  • Feeling things that do not exist: They may scratch or swat at their skin if imagining insects are crawling on them. They may also shout at someone to get off them if they think someone is touching them.
  • Hearing imaginary sounds: A person may startle or ask if anyone else can hear sounds that others in the room cannot.

It is important to distinguish between when a person with dementia misunderstands something and when that person is hallucinating. They may misperceive or misidentify something they saw or heard, which can cause people around them to think they are hallucinating.

Learn more about how to care for someone with dementia.

Often a person with dementia needs support during and after hallucinations, especially if the hallucinations are distressing and frightening.

To support someone experiencing hallucinations, a caregiver may provide physical contact if the person with hallucinations is receptive. If the person is calm and at ease, it is okay to let them be.

The National Institute on Aging (NIA) has the following tips for supporting someone who is hallucinating:

  • Try not to argue with the person about what they are seeing: Comfort the person if they are afraid.
  • Distract the person: Moving to another room or taking the person for a walk may help them.
  • Make sure the person is safe: Try to remove sharp objects or anything that they could use to hurt others or themselves.

Learn more about how to talk with someone with dementia.

To prevent hallucinations, a caregiver can ensure the person with dementia has a clean, clutter-free environment with the correct temperature and brightness.

A caregiver should ensure the person with dementia has one-on-one time with various people, remains active, and engages in enjoyable activities. They can use a journal to record the person’s daily activities, moods, and behaviors.

Learn more about the best activities for people with dementia.

Caregivers should speak with a healthcare professional if a person with dementia is experiencing hallucinations, especially if they become more severe or cause additional mood and behavioral shifts.

A doctor can decide if another health concern is responsible for the hallucinations. Talk with a doctor before changing a person’s medications and check in regularly to see if additional changes are necessary.

Here are some answers to frequently asked questions about hallucinations and dementia.

What stage of dementia produces hallucinations?

Hallucinations usually occur during the advanced stages of dementia.

What triggers hallucinations?

Experts believe brain damage caused by dementia affects sensory processing and triggers hallucinations.

What is the most common type of hallucination in people with dementia?

The most common hallucinations are auditory and visual.

People with dementia may experience hallucinations that affect their senses, especially during the disease’s advanced stages.

Hallucinations can involve seeing, hearing, and smelling things that do not exist. If someone is hallucinating, caregivers need to remain calm and ensure the person is safe from harming themselves or others.

Caregivers should speak with a healthcare professional if a person with dementia is experiencing hallucinations. Doctors can provide advice on the best treatment pathway, which may involve medication or tips to improve the quality of life for a person with dementia.