Dementia serves as an umbrella term for various conditions that cause gradual brain deterioration and memory loss, with Alzheimer's disease representing the most prevalent form.

Alzheimer's typically presents with memory loss and cognitive decline severe enough to disrupt everyday activities, and whilst no cure exists for this condition at present, early detection can decelerate its advancement and help patients or their families maintain better quality of life for longer.

Whilst most people link memory problems with Alzheimer's, research indicates this might not be the initial warning sign, with a comprehensive review published in 2017 proposing that depression could serve as an early red flag.

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The scientists carried out an extensive examination of medical literature spanning from 1937 to 2016 in an effort to catalogue the warning signs and symptoms that occur before an Alzheimer's diagnosis.

Their findings revealed that depression and cognitive decline were the initial symptoms to emerge in 98.5 per cent and 99.1 per cent of participants in a late-onset Alzheimer's study, and nine per cent and 80 per cent respectively in early-onset cases.

Memory problems appeared early and were noted 12 years prior to the clinical diagnosis of advanced Alzheimer's. The scientists concluded that "the findings of this review suggest that neurological and depressive behaviours are an early occurrence.

"However, the study was limited by the fact that each one of the findings was based on a single study," they pointed out. Spotting depression can be a tricky task in itself, let alone when it appears asa symptom of Alzheimer's or another form of dementia.

The Alzheimer's Association (AA) has provided examples of symptoms common to both depression and dementia:

• Apathy


• Loss of interest in activities and hobbies


• Social withdrawal


• Isolation


• Trouble concentrating


• Impaired thinking

"In addition, the cognitive impairment experienced by people with Alzheimer's often makes it difficult for them to articulate their sadness, hopelessness, guilt and other feelings associated with depression," the health organisation observes.

They've also emphasised that depression in those suffering from Alzheimer's may not resemble typical depression, as it might not be as severe and may come and go rather than being a persistent feeling.

They further observed that a person with Alzheimer's may be less likely to talk about or attempt suicide, compared to those suffering solely from depression.