Annals of Long Term Care

To the Editor:

I read with interest the review article by Gellis et al1 about treatment for depression in older persons with dementia. I would like to contribute to the discussion by highlighting three salient observations.

First, depressive features in dementia are often subsyndromal and not severe enough to meet the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM- IV) criteria for major depressive disorder (MDD).2,3 Some authors propose a distinct set of criteria for depression of Alzheimer’s disease (dAD), which is increasingly recognized as a distinct entity from MDD.2 In particular, dAD may be less severe, less persistent with a waxing and waning course, less correlated with psychosocial factors, and exhibit fewer melancholic factors. In contrast to the DSM IV criteria for MDD, the more inclusive dAD criteria require the presence of fewer symptoms (3 instead of 5); do not require the presence of symptoms nearly every day; incorporate irritability, social isolation, and hopelessness as part of the criteria; and revise criteria for anhedonia to reflect decreased positive affect or pleasure in response to social contact and usual activities. Data from population-based cohorts such as the Cache County Study support the use of less restrictive criteria for the determination of depression in dementia.4

Second, just as many guidelines stress the importance of routinely assessing for suicidal risk in any older person who is newly diagnosed with depression, a similar degree of vigilance cannot be overemphasized in the evaluation of depression in dementia.5 Consistent case reports of completed suicides in older persons with dementia highlight the folly of the previously held assumption that the level of risk for suicide in persons with dementia is negliglible. Careful scrutiny of the literature readily reveals a high-risk phenotype predisposing to increased suicidal risk: male gender, highly educated professional, preserved insight, depressive symptoms that need not necessarily meet criteria for major depression and often postdate the onset of cognitive symptoms, and suicidal ideation.6

Last, I would like to draw attention to a recent excellent review of the differential behavioral effects of antidementia drugs, namely cholinesterase inhibitors (ChEIs) and memantine.7 Mood symptoms and apathy were the behavioral domains that most commonly responded to ChEIs, whereas memantine was associated with a reduction in irritability and agitation. However, the authors noted that many of these studies were not designed to test the psychotropic properties of antidementia drugs, and there is substantial variability among trials in terms of behavioral outcomes.

Dr. Wee-Shiong Lim, MBBS, MRCP (UK)
Consultant, Department of Geriatric Medicine
Tan Tock Seng Hospital
Singapore

References

1. Gellis ZD, McClive-Reed KP, Brown EL. Treatments for depression in older persons with dementia. Annals of Long-Term Care: Clinical Care and Aging 2009;17(2):29-36.

2. Olin JT, Schneider LS, Katz IR, et al. Provisional criteria for depression of Alzheimer’s disease. Am J Geriatr Psychiatry 2002;10:125-128.

3. Olin JT, Katz IR, Meyers BS, et al. Provisional diagnostic criteria for depression of Alzheimer’s disease. Rationale and background. Am J Geriatr Psychiatry 2002;10:129-141.

4. Lyketsos CG, Steinberg M, Tschanz JT, et al. Mental and behavioural disturbances in dementia: Findings from the Cache County Study on Memory in Aging. Am J Geriatr Psychiatry 2000;57:708-714.

5. Lapid MI, Rummans TA. Evaluation and management of geriatric depression in primary care. Mayo Clin Proc 2003;78:1423-1429.

6. Lim WS, Rubin EH, Coats M, et al. Early-suicide Alzheimer Disease represents increased suicidal risk in relation to later stages. Alzheimer Dis Assoc Disord 2005;19:214-219.

7. Cummings JL, Mackell J, Kaufer D.