Year: 1997
Type: letter
Abstract: We appreciate the comments of Dr. Friedman and colleagues regarding our paper “Psychotic symptoms in Parkinson's disease with dementia.”1 Their own work and cited unpublished data confirm our concern1 regarding the functional importance of psychotic symptoms in Parkinson's disease (PD). We did not intend, in this brief report, to provide a definitive estimate of the prevalence of psychotic symptoms in all patients with PD. This was a study of PD dementia patients and was derived from a community-based population rather than a research clinic or a sample of early-stage PD patients. Regarding the accuracy of diagnosis of PD, all the patients reported on were evaluated by experienced geriatricians, neurologists, and psychiatrists at academic medical centers. As described in our paper,1 we specifically excluded patients who received a diagnosis of probable or possible Alzheimer's disease (NINCDS criteria), as well as those with vascular dementia or other recognizable neurological syndromes that could cause a movement disorder. Furthermore, as pointed out in the paper, patients taking medications (i.e., neuroleptics) that could cause extrapyramidal symptoms were explicitly excluded. Although there may be some contamination from diffuse Lewy body disease2 (as roughly one-third of the subjects had been evaluated before 1988), this is unlikely to account for the entire prevalence of psychotic symptoms. Interestingly, there was no temporal trend for a decreasing prevalence of psychotic symptoms in PD patients as the diffuse Lewy body disease became increasingly recognized over the past few years. Our paper1 also discussed the study limitation resulting from a lack of medication data. Dopaminergic agents clearly play an important role in producing psychotic symptoms in PD. Whether psychosis cannot be a part of the normal clinical repertoire of untreated PD is, however, difficult to test because it would be hard to find untreated patients with PD dementia. Notably, Sweet et al.3 reported that 10 of their 98 patients had delusions, agitation, and hallucinations before the initiation of a levodopa trial. We look forward to further large clinical series carefully describing psychotic symptoms in PD dementia.
Language: English
Subfield: Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4238023556