Take our Dementia Test

Find a therapist to help with dementia

Lewy body dementia (LBD) is the second-most-common neurodegenerative dementia after Alzheimer’s Disease

LBD symptoms include cognitive and motor declines, hallucinations, and acting out dreams.

People who experience LBD often do not receive a correct diagnosis initially.

Navigating the healthcare system with LBD presents unique challenges.

A reminder from an earlier post: Dementia is not a disease, per se. It is a cluster of symptoms that stem from many potential diseases. The field of gerontology refers to Alzheimer’s Disease and Related Dementias (acronym ADRD). Well, it’s time to take a look at those related dementias. What kind of relatives are they?

Lewy body dementia (LBD) is the second-most-common neurodegenerative cause of dementia, after Alzheimer’s Disease. But it's the most-common cause that doesn’t receive sufficient attention.

You may have heard about Lewy body dementia because actor and comedian Robin Williams had the disease. He received outstanding medical care; he saw specialists and underwent state-of-the-art tests. Before his death, he was diagnosed with Parkinson’s disease and depression, but an autopsy revealed he'd had Lewy body dementia all along, although multiple doctors missed the diagnosis. It just wasn’t on their radar.

Symptoms that LBD Shares with Other Dementias

LBD can start out with motor declines resembling those of Parkinson’s disease; cognitive declines and other symptoms arise later. Or it can start with cognitive changes, with motor symptoms developing later. In other words, it shares symptoms with other dementias in its earliest phases.

People with LBD show emotional, cognitive, and behavioral symptoms common across dementias:

Difficulties thinking and paying attention.

Getting lost and not knowing where they are

Apathy and problems motivating themselves to engage in activities

Anxiety, depression, and changes in mood

They also share motor symptoms of Parkinson’s Disease:

Stiffness, including less facial expression of emotion

Incontinence or problems getting to the toilet on time

Changes in blood pressure control or temperature

Symptoms That Make LBD Different From Other Forms of Dementia

Some symptoms are more common in LBD than in other forms of dementia:

Hallucinations and seeing things that aren’t there

Delusions and believing things that aren’t true

One person with LBD thought their garage was filled with rats, and that the rats started running toward them. Another person deeply believed her spouse was having an affair, even though the spouse was a loving care partner.

Hallucinations are not always frightening to the person experiencing LBD. They might see animals in a friendly way. Hallucinations are often more disturbing to family members who care for them.

Patterns in daily life can also be particularly problematic with LBD:

Sleep disruptions. While other dementias can include ‘sundowning” and wakefulness during the evening, LBD involves disruptions when the person is asleep. Good sleep includes a phase characterized by rapid eye movement, though the eyes are still closed (REM phase). Healthy people dream during the REM phase, but are temporarily paralyzed and don’t move. People with LBD may move during REM sleep. Sometimes they act out their dreams, such as grabbing onto their partner or falling out of bed.

Fluctuations in cognition. One of the most difficult characteristics of LBD involves changes between lucidity (normal functioning) and symptoms such as cognitive difficulties. People living with other dementias have good and bad days, but people with Lewy body dementia can have good and bad hours. That makes it challenging to plan events and social gatherings because things can change moment to moment.

Take our Dementia Test

Find a therapist to help with dementia

Technical Information about Lewy Body Dementia (LBD) and the Brain

OK, now for some technical information: Lewy body dementia includes two types of dementia: dementia with Lewy bodies and Parkinson’s disease dementia. The vast majority of dementia cases are, in fact, Alzheimer’s Disease, but estimates suggest that at least 15% of cases reflect Lewy body dementia. That’s 1 in 7 cases. Not trivial.

As I explained previously, dementia symptoms arise from abnormal deposits of misfolded proteins. In Alzheimer’s disease, one misfolded protein, amyloid-beta, forms plaques. Another protein, tau, forms tangles in the brain. LBD involves abnormal deposits of a different protein, alpha-synuclein, which accumulates as Lewy bodies in the brain and, interestingly, in other organs throughout the body.

To make matters fuzzier, many individuals diagnosed with Alzheimer’s disease have other forms of dementia. Autopsies of people with Alzheimer’s Disease reveal that their brains often include Lewy bodies or vascular dementia. In other words, more than one thing can go wrong in the brain.

This is important because the most effective medical care can vary by dementia type.

LBD and the Healthcare System

The challenges of handling any dementia are real. And it is also true that LBD receives too little attention.

There are resources specific to LBD. The Lewy Body Dementia Association has a wealth of information. You can call and leave a message; the Support Services team will get back to you. Online and in-person support groups for people experiencing LBD and their loved ones are also available.

As with all diseases, access to healthcare is key. LBD responds well to some medications and to lifestyle changes. Medications sometimes prescribed for Alzheimer’s Disease, however, such as antipsychotic medications, can be dangerous for people with LBD. The two forms of dementia have different effects on the brain. So correct diagnosis is particularly important.

As noted above, many doctors are unfamiliar with LBD or overlook how symptoms fit together. So, it may take visits to different healthcare professionals to reach the correct diagnosis.

We have a long way to go in understanding and treating LBD, but, as with any dementia, getting a correct diagnosis and using existing support and healthcare is key to coping with it.

Reminder: A blog post is an opportunity to learn about a topic. It is not medical advice. Talk with your doctor for medical advice. They know which medical information best fits your particular needs.

Kalia, L. V., Ikeda, M., Sultana, J., Chouliaras, L., O’Brien, J. T., & Taylor, J.-P. (2025). The evolving therapeutic landscape of dementia with Lewy bodies. The Lancet Neurology, 24(12), 1038–1052. https://doi.org/10.1016/S1474-4422(25)00323-0

McKeith, I. G., Boeve, B. F., Dickson, D. W., et al. (2017). Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium. Neurology, 89(1), 88–100. https://doi.org/10.1212/WNL.0000000000004058

O’Brien, J. T., Taylor, J.-P., Thomas, A., Bamford, C., Vale, L., Hill, S., Allan, L., Finch, T., McNally, R., Hayes, L., Surendranathan, A., Kane, J., Chrysos, A. E., Bentley, A., Barker, S., Mason, J., Burn, D., & McKeith, I. (2021). Improving the diagnosis and management of Lewy body dementia: The DIAMOND‑Lewy research programme including pilot cluster RCT. NIHR Journals Library. https://doi.org/10.3310/pgfar09070

Pirraglia, E., Osorio, R. S., Glodzik, L., Ashebir, Y., & Shao, Y. (2025). Subtypes of multiple-etiology dementias and the heterogeneous impact of APOE variants. Alzheimer’s & Dementia, 21(11), e70872. https://doi.org/10.1002/alz.70872

There was a problem adding your email address. Please try again.

By submitting your information you agree to the Psychology Today Terms & Conditions and Privacy Policy

© Psychology Today