Classification of psychotic symptoms in dementia with Lewy bodies

The aim of this study is to determine empirically a possible classification of psychotic symptoms, and identify the frequency of such symptoms in dementia with Lewy bodies (DLB).

This was a clinical study of prospectively observed patients from the memory clinic at Shiga Medical Center. The authors conducted a factor analysis of psychotic symptoms in 96 probable DLB and 4 possible DLB patients, clinically diagnosed according to the consensus criteria, were included.

Four factors were obtained. Factor 1 was closely akin to misidentifications, including Capgras syndrome, phantom boarder, and reduplication of people and places. Factor 2 consisted of reduplication of people, the belief that deceased relatives are still alive, and the belief that absent relatives are in the house, which was classified as a type of misidentification or paramnesia. Factor 3 was akin to visual hallucinations of nonhuman objects, and factor 4 mirrored the hallucination of people and feeling of presence. Delusions were independent of these factors. Following the results of factor analysis, the rates of each symptom group were identified. Hallucinations were the most frequent psychotic symptom in DLB (78%), followed by misidentifications (56%) and delusions (25%).

This study suggested that hallucinations, misidentifications, and delusions should be separately considered in understanding of underlying pathophysiology or psychopathology of DLB.