Chinese researchers from Guangzhou Medical University found that patients with depression and obesity had increased levels of inflammatory markers and worsened cognitive functions, including working memory and processing speed. They believe that losing weight in patients with depression will improve brain function. The study was published in the journal Journal of Affective Disorders.
There is a 58% increase in the risk of obesity following major depressive disorder, and obesity has a 55% increase in the risk of subsequent depression. Additionally, both obesity and depression are associated with cognitive decline. Because all three conditions make people vulnerable to other mental and physical illnesses, the researchers decided to further examine their relationships.
The researchers collected data from 265 volunteers with major depressive disorder who were grouped according to their weight. Participants filled out questionnaires to measure their levels of depression and cognition and donated blood for analysis of biomarkers of inflammation.
Analysis of the data showed that participants with depression and obesity were more likely to experience problems with processing speed and working memory than participants without obesity. In addition, people with depression and obesity had high levels of three of the 19 proinflammatory biomarkers: tumor necrosis factor TNF-alpha, interleukin-8 (IL-8) and macrophage inflammatory protein MIP-1-beta. Researchers believe that inflammation may be the cause of cognitive impairment and that it will be necessary to lose weight to recover from it.
“Our results are promising for clinical use, as overweight or obese patients with depression can take measures to control weight and combat inflammation, which will improve cognitive function, particularly information processing speed,” the study’s authors wrote.