Relationship between Dementia Severity and Behavioral and Psychological Symptoms of Dementia in Dementia with Lewy Bodies and Alzheimer's Disease Patients

BACKGROUND/AIMS: Behavioral and psychological symptoms of dementia (BPSD) are common in the clinical manifestation of dementia. Although most patients with dementia exhibit some BPSD during the course of the illness, the association of BPSD with the stage of dementia remains unclear. It was the aim of this study to evaluate the impact of severity of dementia on the expression of BPSD in patients with dementia with Lewy bodies (DLB) and Alzheimer's disease (AD). METHODS: Ninety-seven patients with DLB and 393 patients with AD were recruited from 8 dementia clinics across Japan. BPSD were assessed by the Neuropsychiatric Inventory (NPI). A relationship between BPSD and dementia stage classified by the Clinical Dementia Rating (CDR) in each type of dementia was assessed. RESULTS: No significant difference was seen in NPI total score across CDR staging in the DLB group. On the other hand, the NPI total score significantly increased with dementia stage in the AD group. CONCLUSION: The relationship of dementia stage with the expression of BPSD was different according to the type of dementia. BPSD and dementia stage were correlated in AD subjects, in whom psychiatric symptoms increase as the disease progresses, but not in DLB subjects.