Depressive Störungen bei Demenzen und milder kognitiver Beeinträchtigung: Komorbidität, Ursache oder Risikofaktor?

Abstract

Both depression and dementia occur by themselves or together in elderly subjects aged 65 and above. The aim of this review is to discuss several hypotheses which try to explain the frequent co-occurrence exceeding chance alone, based on a systematic literature search. A series of studies revealed potential biological similarities between both disorders which, however, were not found in all investigations. Lifetime history of depression can be considered as a distant risk factor for dementias. Depression occurs most frequently within one year before and after the onset of dementia, in which the association between both disorders is probably strongest. In a subgroup of subjects with more "cognitive reserve", depression was found to be a consequence of patient's realisation of beginning cognitive deficits. Several studies indicate that depression in Alzheimer and other dementia forms can be considered as a separate disease entity, as the clinical syndrome differs from depression in earlier periods of life. Studies on the therapy of depression in dementia have aroused increasing interest in recent years. Herewith, certain guidelines in the treatment of older patients with antidepressants must be followed.

The risk of developing depression when suffering from neurological diseases

“…Although there have been different mechanisms proposed that could explain comorbidity, such as psychological factors – for instance, a patient noticing that he/she is developing dementia might become depressive – or biological explanations – “vascular depression” – the reason for comorbidity is not well understood [9]. Our finding that most instances of depression are diagnosed in the year after Alzheimer’s/dementia is in line with the literature [26]. Finally, we cannot exclude the fact that patients who suffer from Alzheimer’s/dementia will be treated by specialized physicians who may be more likely to diagnose depression; but we do not have any specific data on this.…”

Effects of Depressive Syndromes on the Everyday Competence of Nursing Home Residents with Dementia

“…In patients with depression and dementia, some studies have displayed a positive effect on the depressive condition. However, side effects were also seen, such as agitation and tremors (Preuss et al, 2009). With regard to the drug treatment of patients with the comorbidity of depression and dementia, a current Health Technology Assessment (HTA) by Banerjee et al (2011) shows that therapy with sertraline or mirtazapine has no efficacy compared to the control group, which received placebo.…”

Similarities Between Depression and Neurodegenerative Diseases: Pathophysiology, Challenges in Diagnosis and Treatment Options

“…The depressive prodrome is one of the earliest manifestations of neurodegenerative diseases, especially Alzheimer's disease [17,18] as well as Parkinson's disease [8]. In such cases, the patient might only be diagnosed with depression and treated inappropriately, and earlier diagnosis and intervention of a neurodegenerative disease can be missed [17].…”

“…However, in Alzheimer's disease and other neurodegenerative diseases, depression can present at any stage of disease evolution [18]. Regardless of the time of presentation, most patients suffering from a neurodegenerative disease suffer from depression at some point during their disease.…”

“…However, a brain that suffers from depression at an earlier age can undergo significant maladaptive structural and functional changes that may predispose it to the process of neuronal degeneration [18,23]. Some studies propose that pseudodementia of depressive illness and depression in neurodegenerative disease are two ends of a spectrum based on Janet's concept of psychological tension [24].…”