Is Psychosis More Common in Certain Types of Dementia?
Alzheimer's, Lewy body, and Parkinson's all have different rates of dementia-related psychosis,
For reasons experts still don't fully understand, different dementias carry different risks of a person developing psychosis, says George Grossberg, M.D., professor and director of geriatric psychiatry at Saint Louis University School of Medicine in Missouri. Learn more about which types are most likely to include DRP.
The question becomes, do we see the dementia-related psychosis more commonly in one type of dementia versus another? I think that's an important issue. First of all, before we answer that, it's important to keep in mind that a lot of patients, in the real world, acquire a diagnosis of dementia. If you ask them or you ask the family, what type of dementia does mom or dad have, often they don't know because the doctor maybe didn't tell them.
We do have the ability to kind of subtype or to more specifically diagnose the various dementias. I'm going to talk about the top five, the big five, as we call them, in order of prevalence. Then we can talk about how common is psychosis or psychotic symptoms, this dementia-related psychosis in each of them, because the frequency really, really does vary.
The most common of all the dementias is Alzheimer's disease, maybe accounting for two thirds or more of all dementing disorders. There, the prevalence of psychosis or psychotic symptoms is probably about a third, maybe a little more than 30% between 30 and 40, perhaps at the most.
The second most common cause of dementia is what's called vascular or stroke-related dementia. There the numbers are less, maybe half, maybe 15% or 20%. Then the third, the next most common type of dementia is called Lewy body dementia, which is very closely related to number four, which is Parkinson's disease dementia.
Lewy body dementia and Parkinson's disease dementia form a spectrum. Together they're actually quite common and they have by far the highest prevalence of psychotic symptoms, maybe three-quarters. Abuot 60%, 70%, 75% of both Lewy body and Parkinson's disease dementia patients will experience psychotic symptoms.
The least common of the top five is what we call frontotemporal, used to be called Pick's disease, frontotemporal dementia. That it is relatively rare, maybe 10%. That's the least common as far as where we see the prevalence of psychotic symptoms or this dementia-related psychosis.