Treat Depression - Prevent Dementia
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The association between depression and cognitive decline has been the subject of considerable investigation and discussion. Recent findings indicating that depression is a risk factor for Alzheimer’s disease (AD) dementia have raised the possibility that depression treatment may lead to prevention of cognitive decline and dementia.
The U.S. government's National Institutes of Health put together the following consensus study. It summarizes the available evidence regarding the association between depression and Alzheimer's dementia.
It addresses the question of whether treating depression may succeed in reducing Alzheimer's risk.
What Is the Relationship of Depression in Older People With Risk of Developing Alzheimer's Disease or Age-Related Cognitive Decline?
Depressive symptoms affect about 15% of people over 65, with major depression affecting about 4%. A 2006 meta-analysis involving data from 20 studies and 102,172 individuals estimated that depression approximately doubles the risk for Alzheimer's dementia.1
Since the publication of that study, two cohort studies from the United States2–3 and studies from Spain,4 Canada,5 and The Netherlands6 have confirmed this association, with one study failing to confirm.7
Uncertainty remains regarding the characteristics of depression that most strongly predict Alzheimer's risk. In general, the association is strongest for moderate or more severe depression, especially major depression. The data are contradictory regarding the role of age of onset of depression, although most studies suggest that late-onset depression is most closely associated with dementia.
One Dutch study, in which age of onset was retrospectively assessed, suggests that early-onset depression confers greater risk.6 Data from the Baltimore Epidemiologic Catchment Area Study, where depression age of onset was ascertained prospectively early in life, do not support early-onset depression as a risk factor for cognitive decline or dementia 20 years later.
Some studies suggest that the depression-dementia association is stronger in men, while others suggest it is stronger in women. The Honolulu-Asia Aging Study reported that the depression-dementia association may be limited to ApoE4 carriers. In the Cache County Study, we find late-onset depression, especially major depression, but not early-onset depression to be a risk factor for Alzheimer's, independent of other variables and apoliproprotein E (APOE) genotype.
Depression and other neuropsychiatric symptoms (NPS) such as apathy, irritability, anxiety, and agitation affect as many as 50% of individuals with mild cognitive impairment (MCI),8,9 and are comparably prevalent in amnestic and nonamnestic MCI.10
Several studies on MCI have reported an association between NPS and transition to dementia,11,12 although a recent study reported an inverse association between NPS and dementia incidence.13 In one study, major depression in MCI conferred a 2.6-fold increased risk for Alzheimer's.14 Late-life onset “mild behavioral impairment” is a strong risk factor for dementia, both in the presence and absence of MCI.15 An examination is underway of the predictive value of NPS in MCI using the large MCI cohort of the National Alzheimer’s Coordinating Center (n>4,000), allowing for nuanced study.
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Footnote References
- Ownby RL, Crocco E, Acevedo A, John V, Loewenstein D. Depression and risk for Alzheimer disease: systematic review, meta-analysis, and metaregression analysis. Arch Gen Psychiatry. 2006;63(5):530–538.
- Luchsinger JA, Honig LS, Tang MX, Devanand DP. Depressive symptoms, vascular risk factors, and Alzheimer’s disease. Int J Geriatr Psychiatry. 2008;23(9):922–928.
- Irie F, Masaki KH, Petrovitch H, et al. Apolipoprotein E epsilon4 allele genotype and the effect of depressive symptoms on the risk of dementia in men: the Honolulu-Asia Aging Study. Arch Gen Psychiatry. 2008;65(8):906–912.
- Fernández Martínez M, Castro Flores J, Pérez de Las Heras S, Mandaluniz Lekumberri A, Gordejuela Menocal M, Zarranz Imirizaldu JJ. Risk factors for dementia in the epidemiological study of Munguialde County (Basque Country-Spain). BMC Neurol. 2008;8:39.
- Stepaniuk J, Ritchie LJ, Tuokko H. Neuropsychiatric impairments as predictors of mild cognitive impairment, dementia, and Alzheimer’s disease. Am J Alzheimers Dis Other Demen. 2008;23(4):326–333. Epub 2008 May 4.
- Geerlings MI, den Heijer T, Koudstaal PJ, Hofman A, Breteler MM. History of depression, depressive symptoms, and medial temporal lobe atrophy and the risk of Alzheimer disease. Neurology. 2008;70(15):1258–1264.
- Becker JT, Chang YF, Lopez OL, et al. Depressed mood is not a risk factor for incident dementia in a community-based cohort. Am J Geriatr Psychiatry. 2009;17(8):653–663.
- Lyketsos CG, Lopez O, Jones B, Fitzpatrick AL, Breitner J, DeKosky S. Prevalence of neuropsychiatric symptoms in dementia and mild cognitive impairment: results from the Cardiovascular Health Study. JAMA. 2002;288(12):1475–1483.
- Geda YE, Roberts RO, Knopman DS, et al. Prevalence of neuropsychiatric symptoms in mild cognitive impairment and normal cognitive aging: population-based study. Arch Gen Psychiatry. 2008;65(10):1193–1198.
- Rosenberg PB, et al. Neuropsychiatric Symptoms in MCI Subtypes: The Importance of Executive Dysfunction. 4th Congress of International Society for Vascular Behavioral and Cognitive Disorders, Singapore, January 14–16, 2009.
- Palmer K, Berger AK, Monastero R, Winblad B, Bäckman L, Fratiglioni L. Predictors of progression from mild cognitive impairment to Alzheimer disease. Neurology. 2007;68(19):1596–1602.
- Liu HC, Wang PN, Wang HC, et al. Conversion to dementia from questionable dementia in an ethnic Chinese population. J Geriatr Psychiatry Neurol. 2007;20(2):76–83.
- Ramakers IH, Visser PJ, Aalten P, Kester A, Jolles J, Verhey FR. Affective symptoms as predictors of Alzheimer’s disease in subjects with mild cognitive impairment: a 10-year follow-up study. Psychol Med. Epub 2009 Nov 11:1–9.
- Modrego PJ, Ferrández J. Depression in patients with mild cognitive impairment increases the risk of developing dementia of Alzheimer type: a prospective cohort study. Arch Neurol. 2004;61(8):1290–1293.
- Taragano FE, Allegri RF, Krupitzki H, et al. Mild behavioral impairment and risk of dementia: a prospective cohort study of 358 patients. J Clin Psychiatry. 2009;70(4):584–592. Epub 2009 Mar 24.
Source:
"Risk Reduction Factors for Alzheimer’s Disease and Cognitive Decline in Older Adults: Depression and Related Neuropsychiatric Disturbances". Constantine G. Lyketsos, M.D.; Christopher Marano, M.D.; Maria Norton, Ph.D.; JoAnn Tschanz, Ph.D.; Gwenn Smith, Ph.D.; Paul Rosenberg, M.D.; Hochang Ben Lee, M.D.; David B. Steffens, M.D.
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