What is the association between depression and Alzheimer’s disease?

Abstract

Depression and dementia, in particular Alzheimer’s disease (AD), are critically important issues in the mental health of old age. Both conditions apparently reduce quality of life and increase the impairment of activities of daily living for elderly persons. AD usually shows poor prognosis owing to progressive neuronal degeneration, while depression is basically reversible. However, depressive symptoms are common in AD and occur in approximately 20–30% of patients with AD. Epidemiological studies have shown a possible pathological association between depression and AD. Some longitudinal studies have reported that depression is a prodromal sign or might be both a prodromal symptom of AD and a risk factor. Other studies have suggested that depressive symptoms appear to coincide with or follow the onset of AD rather than precede it. However, it still remains controversial whether depressive symptoms represent a risk factor for AD, whether they are an early symptom of neurodegeneration, or whether they are a reaction to early cognitive deficits. A better understanding of the link between AD and depression might have important clinical and research implications. This review provides an overview of current knowledge regarding a relation between depression and AD and also proposes a research and clinical perspective on depression in AD.

Keywords::

• Alzheimer’s disease
• antidepressant
• dementia
• depression
• risk factor

Financial & competing interests disclosure

This work is partially supported by a Grant in Aid for Scientific Research for the Ministry of Education, Culture, Sports, Science and Technology of Japan and by a Grant from St Luke’s Science Institute of Tokyo. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.