Anxiety may accelerate the progression of mild cognitive impairment into Alzheimer’s, research suggests.
The memory-robbing disease is thought to come about when abnormal clusters of the protein amyloid-beta forms plaques between nerve cells in the brain, causing tissue to die and the vital organ to shrink.
In the early stages, a patient may endure memory lapses that cause them to forget recent conversations, misplace items or have trouble finding the right word.
Vague symptoms mean mild Alzheimer’s is often mistaken for anxiety, however, scientists from the Medical University of South Carolina in Charleston have found the mental-health condition could accelerate the disease’s progression.
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After looking at 339 people with mild cognitive decline, the team found those showing anxiety symptoms developed Alzheimer’s faster, irrespective of how much brain volume they lost or if they were genetically at-risk of the memory-robbing condition.
Alzheimer’s is the most common form of dementia, the umbrella term for a range of conditions that cause a decline in brain function.
Of the around 850,000 people in the UK with dementia, between half (50%) and three quarters (75%) have Alzheimer’s. In the US, more than 5 million people have the disease.
Alzheimer’s is progressive, with the rate of decline varying between patients.
Most first endure mild cognitive impairment, defined as a loss in memory and thinking skills beyond that which is normally associated with ageing.
Anxiety is often observed in patients with mild cognitive impairment, however, its role in disease progression was poorly understood.
“We know volume loss in certain areas of the brain is a factor that predicts progression to Alzheimer’s disease,” said study author Dr Maria Vittoria Spampinato.
“In this study, we wanted to see if anxiety had an effect on brain structure, or if the effect of anxiety was independent from brain structure in favouring the progression of disease.”
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The scientists looked at 339 patients, with an average age of 72, who took part in the Alzheimer’s Disease Neuroimaging Initiative 2 study.
Each patient had been diagnosed with mild cognitive impairment, with 72 progressing to Alzheimer’s, while the remaining 267 remained stable.
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Brain MRI scans were taken to determine a loss in volume to the hippocampus and entorhinal cortex, two regions that are important in memory formation.
The patients were also tested for variation to the gene ApoE4, one of the most prevalent risk factors for Alzheimer’s. Anxiety was measured via clinical surveys.
As expected, the patients who progressed to Alzheimer’s had significantly lower volumes in their hippocampus and entorhinal cortex, as well as a greater frequency of the ApoE4 genetic variation.
Most notably, the scientists found anxiety was associated with cognitive decline.
“Mild cognitive impairment patients with anxiety symptoms developed Alzheimer’s disease faster than individuals without anxiety, independently of whether they had a genetic risk factor for Alzheimer’s disease or brain volume loss,” said co-author Jenny Ulber, a medical student.
Better understanding the link between anxiety and Alzheimer’s may allow medics to screen patients with mild cognitive impairment, gauging their risk of developing the memory-robbing disease, according to the scientists.
“We need to better understand the association between anxiety disorders and cognitive decline,” said Dr Spampinato.
“We don’t know yet if the anxiety is a symptom – in other words, their memory is getting worse and they become anxious – or if anxiety contributes to cognitive decline.
“If we were able in the future to find anxiety is actually causing progression, then we should more aggressively screen for anxiety disorders in the elderly.”
Ulber added: “The geriatric population is routinely screened for depression in many hospitals, but perhaps this vulnerable population should also be assessed for anxiety disorders.
“Middle-aged and elderly individuals with high level of anxiety may benefit from intervention, whether it be pharmacological or cognitive behavioural therapy, with the goal of slowing cognitive decline.”
The scientists stressed their results, published at the annual Radiological Society of North America meeting, were based on MRI scans done at one point in time.
“We’re now interested in looking at changes over time to see if anxiety has an effect one way or the other on how fast the brain damage progresses,” said Dr Spampinaton.
“We will also take a closer look at gender differences in the association between anxiety and cognitive decline.”
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