Study Ties Depression in Seniors to Risk of Alzheimer's Disease

Most of the aging population develops depression and this could be a major risk factor of developing Alzheimer's faster than others as researchers found that depression leads to the increase of a naturally occurring protein in the brain called beta-amyloid that is a hallmark of Alzheimer's disease.

Alzheimer's is an incurable neurodegenerative disease that develops before noticeable cognitive decline and memory loss.

One of the most prevalent forms of dementia is Alzheimer's and it is estimated that over 44.4 million people worldwide are living with the condition.  According to the 2013 data from the Alzheimer's Disease International, this number is expected to soar by 2030 as 75.6 million of them will be diagnosed with the disease and by 2050 the number will go up to 135.5.

"Our results clearly indicate that mild cognitively impaired subjects with depressive symptoms suffer from elevated amyloid-levels when compared with non-depressed individuals," said the study's principal scientist Axel Rominger, MD, from the department of nuclear medicine at the University of Munich in Germany. "The combination of elevated amyloid-levels and coexisting depressive symptoms constitute a patient population with a high risk for faster progression to Alzheimer's disease."

The study included 371 patients with mild cognitive impairment who underwent PET imaging with radiotracer F-18 florbetapir and MRI. The subjects were chosen from Alzheimer's Disease Neuroimaging Initiative database. The study also included data from 55 different research centers across the U.S. and Canada.

On analyzing the data the researchers noticed that mild cognitive impaired patients with depressive symptoms had an increased deposition of amyloid when compared to their non-depressed counterparts, especially in the frontal cortex and anterior and posterior gyrus of the brain. Both these regions are involved in mood disorders like depression.

"Therapeutic options for Alzheimer's disease are still limited and therefore the identification and understanding of contributing risk factors that influence the disease are crucial in ongoing research as they offer the possibilities for future medical intervention," said co-author and fellow researcher Matthias Brendel.

The finding was presented at the Society of Nuclear Medicine and Molecular Imaging's 2014 Annual Meeting.