WESTWOOD—In the November issue of the journal Archives of General Psychiatry, researchers from UCLA present results of a new study. The study involved using a brain scan to evaluate levels of amyloid plaques and tau tangles in older adults suffering from a depression known as major depressive disorder, or MDD.

It has previously been observed that the plaque and tangle deposits, which are widely known to be precursors of Alzheimer’s as well as dementia, could be seen not only in memory loss, but also in middle-aged and older individuals with mild depression and anxiety.

The scientists were also able to create FDDNP, a chemical marker that is able to bind to both plaque and tangle deposits, making it easier to view them through a positron emission tomography (PET) scan. The team was then able to find where in the brain deposits of tangles and plaque seem to be accumulating.

According to the news release announcing the findings, it was discovered that patients with MDD had an accumulation of tangles and plaques that was higher in the brain, especially around the parts of the brain that are responsible for decision-making, complex reasoning, memory and emotions.

"This is the first study using FDDNP to assess the abnormal protein levels in brains of older adults with severe depression," said the study's senior author, Gary Small, UCLA's Parlow-Solomon professor on aging and a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior. "The findings suggest that the higher protein load in critical brain regions may contribute to the development of severe depression in late life."

It was also found through this study that the protein deposit patterns can often be associated with differing clinical symptoms. For example, some patients in the study showed signs of depression only, while some showed signs of mild cognitive impairment.

Anand Kumar, the Lizzie Gilman professor and department head of psychiatry at the University of Illinois at Chicago, commented on the study saying, "We may find that depression in the elderly may be an initial manifestation of progressive neurodegenerative disease. Brain scans using FDDNP allow us to take a closer look at the different types of protein deposits and track them to see how clinical symptoms develop."

The study was funded by the National Institutes of Health (NIH) as well as the U.S. Department of Energy.

Abnormal protein deposits in MDD brain. Photo courtesy of UCLA.

The team is planning further research in collaboration with Kumar and University of Illinois at Chicago to investigate the importance of APOE-4, a genetic marker that is also a risk factor for Alzheimer’s disease and dementia. In correspondence with Small regarding this matter, Canyon News learned that more government assistance would be sought in order to continue work on the study.

Dr. Kumar informed Canyon News that he and Dr. Small met while working on a geriatric psychiatry study. Dr. Small at the time was working with dementia while he was working with later life depression.

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