With dementia on the rise an expert has warned about a common mental health disorder connected to the mind-destroying disease.
Over one in 10 adults in the US over the age of 65 have it and one in three seniors die with Alzheimer's or another dementia.
Dr Nicole Purcell, a practising neurologist and senior director of clinical care at the Alzheimer's Association, warned about a measurable connection between depression and dementia.
This comes as diagnosed depression soars.
A recent Gallup poll found 29 per cent of US adults report having been diagnosed with depression at some point in their lifetime - this has shot up 10 per cent since 2015.
Although dementia research has come along vastly in 20 years, there is still much scientists are trying to figure out.
Citing depression, anxiety and dementia, Dr Purcell told The Mirror: “They are related somehow.
"But one leads into the other or one causes the other is unclear.”
It means depression developing can be an indicator of dementia.
Dr Purcell said: “We generally recommend that if a patient is not functioning at their baseline whether it be psychiatric or behavioural symptoms.
"Maybe they’re depressed when they’ve never had depression. A change in function.”
Muddying the waters are the many ways dementia develops and presents its ugly self with patients.
According to Dr Purcell although the most common symptom is issues around memory but there's not just one clear tell-tale sign of dementia.
She said: "So it’s not a one size fits all situation. There isn’t just one symptom, I’d like there to be."
Dr Purcell added: "There are things we call 'dementia mimickers'.
"Things like vitamin deficiency (B12/B1) can cause difficulties with memory. Depression can cause memory difficulty in of itself.
"That gets treated and often the memory issues disappear or improve.
"Things like medication patients are on. So there are different things that cause dementia-like symptoms.”
It’s in diagnosis when the connection between dementia and depression appears.
She continued: "We check their medication list, we do blood work to make sure there's no kidney, liver or thyroid dysfunction that would be causing these symptoms.
“We treat any depression or anxiety. To make sure we can rule out other causes for dementia-like symptoms."
For decades little could be done to alleviate the symptoms of dementia but in the last 20 years the field has come along in leaps and bounds.
New pills are now coming onto the market which can slow cognitive decline in dementia patients but them being widely accessible is still some way off.
Instead life-style changes can make a huge difference.
Dr Purcell said: "We generally say what is good for the heart is good for the brain. So discontinuing any cigarette or alcohol use. Making sure blood pressure is controlled, diabetes is controlled."
She also emphasised staying socially and mentally active can help, adding: "Crosswords puzzles, learning something new or, I say, even just trying something you usually do in the day, try and do it differently.
"Social interaction also seems to be a significant risk factor that you can improve.
"So staying socially, physically and mentally engaged is incredibly important. The risk of dementia can be reduced around 40 percent if you make lifestyle changes mid life. It is a huge difference."
Anyone who is worried about themselves or a loved one can go to the Alzheimer's Association website where there is a 24-hour, seven-days-a-week phone line where you can get advice on resources in their area and get connected to the right people.
Dr Purcell said: "There is a fear factor. And there is a stigma factor but just get it checked."
