Clinical Pharmacy & Pharmacogenomics Life

憂鬱與失智症之間的存在著許多糾葛、糾纏與糾結：據研究指出，憂鬱可能是 Alzheimer’s disease 與失智症的風險因子與前驅症狀 (prodrome)，而在失智症的每個階段中，都有可能會發併發憂鬱的情形。
The relationship between depression and dementia is complex: depression has been reported to be both a risk factor and a prodrome for Alzheimer’s disease and dementia, and is a common complication of dementia at all stages.

目前在證據上，對於輕度認知障礙 (mild cognitive impairment, MCI) 病人是否會因憂鬱而使病程進程為失智症，仍是呈現不一致的看法。
There is inconsistent evidence that the presence of depression increases the conversion rate to dementia in patients with mild cognitive impairment.

約有 20-30% 的 Alzheimer’s disease 患者會產生憂鬱的狀況，而且在血管型失智症 (vascular dementia, VoD) 和路易氏體失智症 (dementia with Lewy bodies, DLW) 的病人中發生憂鬱的比例更高。
Depression occurs in 20–30% of patients with Alzheimer’s disease, and is even higher in patients with vascular dementia and dementia with Lewy bodies.

有一收納 1239 位高齡患者為對象之 Baltimore 縱向追蹤研究，共追蹤達 24.7 年，並每隔 1-2 年便進行憂鬱情形的評估，研究發現憂鬱的發作次數是失智症的風險因子，每發作一次憂鬱，便可能提高 14% 的失智症風險。
( Wind: 我這麼憂鬱...  該不會到 40 歲之前就連回家的路都不認得了吧... so sad ~ )
In Baltimore Longitudinal Study of Aging, 1239 elderly participants were followed for 24.7 years and depression was assessed at 1–2-year intervals. The risk for dementia was associated with number of depressive episodes, and increased by 14% for every episode of depression.

在老人的憂鬱通常是複雜且多因性的，可能與心理、基因和大腦改變等狀況有關。其中潛在性大腦改變可能與末期憂鬱有關，包括單胺異常、腦血管疾病、Alzheimer’s disease 與路易士體病變、高類固醇血症之毒性物質壓力、神經發炎、以及神經新生與神經營養物質的改變等。
Depression in older patients is complex and multifactorial, and may be attributed to psychosocial, genetic and brain changes as well as medical conditions. Potential brain changes contributing to late-life depression include monoaminergic changes, cerebrovascular disease, Alzheimer’s disease and Lewy body pathology, and toxic stress, with hypercortisolemia, neuroinflammation, and alterations of neurogenesis and neurotrophic factors.

目前雖然有數個研究試圖探討憂鬱於失智症的機轉，但目前並無一致的實驗結果，因此至今其病因學仍尚未完全明瞭。
The relatively few studies exploring the mechanisms underlying depression in dementia have yielded inconsistent findings, and thus the etiology is unknown.

在憂鬱於失智症之治療方面，目前也缺乏較佳的證據指出那些抗憂鬱藥物對於失智症患者會是較有效的選擇。
There is inconsistent evidence supporting the use of antidepressants for depression in people with dementia.

Reference:

[1] Enache D, Winblad B, Aarsland D. Depression in dementia: epidemiology, mechanisms, and treatment. Curr Opin Psychiatry. 2011 Nov;24(6):461-72.

[2] Teng E, Ringman JM, Ross LK, et al. Diagnosing depression in Alzheimer disease with the national institute of mental health provisional criteria. Am J Geriatr Psychiatry 2008; 16:469–477.

[3] Dotson VM, Beydoun MA, Zonderman AB. Recurrent depressive symptoms and the incidence of dementia and mild cognitive impairment. Neurology 2010; 75:27–34.

[4] Barnes DE, Yaffe K. The projected effect of risk factor reduction on Alzheimer’s disease prevalence. Lancet Neurol 2011; 10:819–828.

[5] Richards E, Reitz C, Devanand D, et al. Relation of late life depression with MCI and dementia: early symptom or risk factor? Alzheimers Dement 2011;7 (Suppl 1):S597–S598; P593-263.

[6] Wetzels RB, Zuidema SU, de Jonghe JF, et al. Course of neuropsychiatric symptoms in residents with dementia in nursing homes over 2-year period. Am J Geriatr Psychiatry 2010; 18:1054–1065.

[7] Ballard CG, Jacoby R, Del Ser T, et al. Neuropathological substrates of psychiatric symptoms in prospectively studied patients with autopsyconfirmed dementia with lewy bodies. Am J Psychiatry 2004; 161:843–849.

[8] Casanova MF, Starkstein SE, Jellinger KA. Clinicopathological correlates of behavioral and psychological symptoms of dementia. Acta Neuropathol 2011; 122:117–135.

[9] Bains J, Birks JS, Dening TR. The efficacy of antidepressants in the treatment of depression in dementia. Cochrane Database Syst Rev 2002; 4: CD003944.

Wind Wei-Lun Chang

8 Nov. 2011