Scientists have long studied risk factors — like depression — that could lead to Alzheimer's. But a recent study took a more specific approach and looked at the symptoms of depression — like anxiety — itself. It found that signs of anxiety could be indicators of Alzheimer's in its beginnings.
"When compared to other symptoms of depression such as sadness or loss of interest, anxiety symptoms increased over time in those with higher amyloid beta levels in the brain," lead researcher and geriatric psychiatrist Nancy Donovan said in a statement.
Amyloid beta is a protein with a long-established connection to Alzheimer's. It builds up in the brain, creating plaques that disorder neuron communication — what is believed to be the primary cause of the disease's signature symptom, cognitive impairment.
But now scientists believe that neuron disruptions might begin as far back as 10 years before noticeable memory decline.
For the study, the research team analyzed data from the Harvard Ageing Brain Study, a five-year look at 270 healthy adults between the ages of 62 and 90. Over the years of the study, the volunteers underwent routine brain scans and were examined for any signs of depression. They found that those with increasing anxiety symptoms also had higher levels of amyloid beta in their brains.
"This suggests that anxiety symptoms could be a manifestation of Alzheimer's disease prior to the onset of cognitive impairment," Donovan said. "If further research substantiates anxiety as an early indicator, it would be important for not only identifying people early on with the disease, but also treating it and potentially slowing or preventing the disease process early on."
The researchers said that a larger study focusing on anxiety and its relationship with amyloid beta and Alzheimer's is needed to further corroborate these initial findings, but that anxiety testing could be a useful tool in determining if a person is at increased risk of developing the disease.
"This is not a definitive result," Donovan told the Boston Herald, "but it does strengthen the argument that neuropsychiatric changes might be associated with this amyloid. As a screening mechanism, it's probably not sensitive enough, but if you can measure multiple risk factors in the same individuals, then it becomes more useful."