NEW RESEARCH SUGGESTS A link between depression and cognitive decline in otherwise healthy aging adults, according to a study published this week. Previous studies have linked depression and anxiety to increased risk for dementia, but ananalysis by researchers at the University of Sussex involving previous studies suggests depression can cause the brain to age faster.
Examining 34 studies that contained more than 71,000 patients, researchers found a strong correlation between depression and brain aging – includ
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“Our populations are aging at a rapid rate and the number of people living with decreasing cognitive abilities and dementia is expected to grow substantially over the next thirty years,” said Dr. Darya Gaysina, a lead author on the paper and lecturer at the University of Sussex.
In conducting their analysis, which was published in the journal Psychological Medicine, researchers excluded patients who demonstrated symptoms of dementia in baseline assessments so as to be able to only consider those adults who were otherwise aging normally.
The researchers acknowledged limitations to their conclusions because the studies used in the analysis employed different methodologies and multiple assessments of depression. They also noted that it is believed that dementia can have up to a decadeslong preclinical period, and so some patients with dementia who were not yet experiencing symptoms may have been unknowingly included in the study.
“It is possible that participants who transition to dementia at follow-up assessment may have already developed substantial cerebral pathology by the time of baseline assessment, even if they were not yet presented with any cognitive symptoms,” the researchers explained in the study. “In this case, associations between affective disorders and development of dementia may be the result of reverse causality.”
The researchers suggested three theories for the link between depression and cognitive decline, which they said were not mutually exclusive and, in fact, likely to overlap: that depression could be a cause of cognitive decline, that depression could in fact be an early symptom of the same underlying conditions that cause the decline, and third, that the causes of depression and automatic decline are separate conditions that share risk factors and underlying causes.
“It is more likely that a complex interaction of biological and socio-behavioral mechanisms are involved in linking affective problems with cognitive decline, rather than one single etiological determinant,” they write.
“Our findings should give the government even more reason to take mental health issues seriously and to ensure that health provisions are properly resourced,” Gaysina said. “We need to protect the mental wellbeing of our older adults and to provide robust support services to those experiencing depression and anxiety in order to safeguard brain function in later life.”
According to the Anxiety and Depression Association of America, major depressive disorder affects more than 16 million adults in any given year.
By Gabrielle Levy covers politics for U.S. News & World Report.
