Dementia with Lewy bodies is associated with higher scores on the Geriatric Depression Scale than is Alzheimer's disease.

BACKGROUND: Several reports suggest a higher morbidity of depression in patients with dementia with Lewy bodies (DLB) than in patients with Alzheimer's disease (AD). However, these results have not been duplicated consistently. The psychiatric symptoms of dementia, including depression, are important for its diagnosis and management. Thus, the aim of the present study was to clarify the characteristics of the depressive symptoms in DLB compared with AD using the Geriatric Depression Scale (GDS).

METHODS: We examined the GDS score for 86 patients with probable DLB (based on the Consensus Criteria for the clinical diagnosis of DLB) and 86 patients with probable AD (based on criteria of the National Institute for Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association), who were matched according to age, sex, education, and Mini-Mental State Examination (MMSE) scores. We also examined correlations between GDS scores and age, sex, or MMSE scores in both groups. Correlations between GDS scores and metaiodobenzylguanidine (MIBG) scintigraphy were examined in patients with DLB. To characterize the GDS in DLB, its profile was examined using factor structures.

RESULTS: Scores for DLB patients were twice as high on the GDS as those for AD patients. There was no correlation between GDS score and age, sex, or MMSE scores in either group. Furthermore, there was no correlation between the results of MIBG scintigraphy and GDS scores in the DLB group. Using factor structures, the depression symptom profile of these diseases suggested that depression-specific symptoms, such as mood, worry, or future outlook, were more frequent in the DLB group than non-specific symptoms, such as lack of energy, decreased concentration, or apathy.

CONCLUSIONS: The data suggest that depressive symptoms are highly specific symptoms of DLB, independent of other features of this disorder. The GDS could be used as a subsidiary tool in differentiating DLB from AD and is more useful than clinical observations of depression.