This Norwegian study looked at 223 people with dementia in western Norway. The researchers' conclusion was: "Depression is common even in mild dementia, and more common and severe in DLB [dementia with Lewy bodies] compared to AD." One downside to the study is that none of the diagnoses for the 223 were confirmed upon brain autopsy. Since the diagnostic accuracy of both DLB and AD are rather low, there's not as much value to these studies as ones that rely on autopsy-confirmed diagnoses.
Robin



International Journal of Geriatric Psychiatry. 2011 Oct;26(10):1054-61. Epub 2010 Oct 28.

Depression in mild dementia: associations with diagnosis, APOE genotype and clinical features.

Fritze F, Ehrt U, Sønnesyn H, Kurz M, Hortobágyi T, Nore SP, Ballard C, Aarsland D.
Department for Geriatric Psychiatry, Psychiatric Clinic, Stavanger University Hospital, Hillevåg, Stavanger, Norway.

Abstract
BACKGROUND:
Depression is common in dementia, with important clinical implications. Few studies of depression in dementia with Lewy bodies are available, and the results are inconsistent.

OBJECTIVE:
To examine the frequency of depression and its characteristics and correlates, in people with mild dementia.

METHODS:
All referrals for patients with a first time diagnosis of dementia to geriatric and older psychiatry outpatient clinics in the counties of Rogaland and Hordaland in Western Norway from March 2005 to March 2007 were screened for the study. Participants and their caregivers underwent a comprehensive and standardised diagnostic and assessment procedure. The depression subitem of the neuropsychiatric inventory (NPId) and Montgomery and Åsberg depression rating scale (MADRS) were used to estimate depression. Cut-off scores for any depression were 0/1 (NPId) and 6/7 (MADRS), and for clinically significant depression 3/4 and 14/15, respectively.

RESULTS:
Two hundered and twenty-three subjects with dementia participated, of whom 59 and 50% showed symptoms of depression assessed by NPI or MADRS, respectively, and 25 and 16% had clinically significant depression as measured by NPI and MADRS, respectively. Depression was more frequent in dementia with Lewy bodies (DLB) than in Alzheimer's disease (AD; p < 0.05). APOE genotype was available in 153 patients, and in AD, but not in DLB, a general linear model showed that the presence of APOE4 allele was significantly associated with depression (F = 4.14; p = 0.045).

CONCLUSION:
Depression is common even in mild dementia, and more common and severe in DLB compared to AD. Future studies should explore the longitudinal course of depression in DLB, and the neural underpinnings of depression in DLB.

Copyright © 2010 John Wiley & Sons, Ltd.

PubMed ID#: 21905099 (see pubmed.gov for this abstract only)

Thanks.

I guess the conclusion that depression is common in dementia is valid. (But, duh ...) I agree that comparing AD with LBD when you don't have confrimed diagnosis is not particularly useful.

It is hard to understand why good money supports these kinds of studies.