it is known in the neuropsych world that patients with specific diagnoses of
lewy body dementia
are actually worse when taking antipsychotic medications, **because while it helps with the hallucinations/psychosis part of the disease, it drastically impairs motor functioning, which in these patients is often parkinsonian-like to begin with.** the challenge is prompting the md's to test for lewy body dementia in a typical "dementia" patient.
in addition, the words "alzheimer's" and "dementia" are becoming increasingly interchangeable even though "alzheimer's" is a specific diagnosis that is supported by batteries of neuropsych tests, and often including ct and mri imaging over time.
eta: in my personal experience, i have witnessed much larger antipsychotic doses prescribed in an attempt to control symptoms in this population with marginal to no effect. sadly, often family's wishes are given more credence in this population than what would be the best for the patient.