Neuropsychiatric symptoms (NPS) can be observed in mild cognitive impairment (MCI) and dementia. Hallucinations are a core clinical symptom of Dementia with Lewy Bodies (DLB). In this study, we investigated NPS in healthy control and MCI groups who would later be diagnosed with DLB to determine which symptoms would present early.

Participants included those originally diagnosed as healthy controls (n=55), MCI with DLB etiology (n=215), and DLB (n=1059). The control and MCI groups progressed to DLB at later visits in the study. NPS data were collected using the Neuropsychiatric Inventory Questionnaire (NPI-Q) that was obtained from the National Alzheimer's Coordinating Center.

To determine which NPS presented early in the DLB course, we ran ANCOVAs to assess the role of original diagnosis on each NPS, using age as a covariate and applying Bonferroni correction. The control and MCI groups, who were later diagnosed with DLB, had greater severity of delusions, hallucinations, agitation, and apathy than the DLB group. The MCI group that would later be diagnosed with DLB had greater severity of anxiety and motor symptoms than the DLB group. The control group had greater irritability severity than the DLB group, and the controls had greater nighttime behavior severity than the MCI group, who had greater severity than the DLB group.

Overall, we found that NPS present early in those who will be diagnosed with DLB, even when they are diagnosed as healthy controls. These results suggest that examination of NPS is important even in healthy adults, and their presence may be the onset of the DLB process before an official diagnosis of the condition.