Long-term fluctuations in depressive symptoms are not associated with other brain health markers in middle age, according to new research published in Journal of Psychiatric Research. The findings suggest that the link between depressive symptom trajectories and brain health may only emerge at the end of life.
“As psychiatric epidemiologists, our goal is to advance the understanding of the development, determinants and consequences of psychiatric phenotypes such as depressive symptoms,” said study authors Annemarie Luik and Isabel Schuurmans from Erasmus MC University Medical Center Rotterdam.
“With the help of this study, we wanted to distinguish how depressive symptoms develop over time, and how these symptom trajectories are associated with subsequent brain health. This information can in turn inform the development of interventions and treatments to promote brain health in individuals with depression. “
For their study, the researchers analyzed data from 1,676 participants from the Origins of Alzheimer’s Disease Across the Life Course (ORACLE) study, which conducted follow-up assessments of previously pregnant women and their partners who had a birth date between April 2002 and January 2006.
The mothers and their partners completed assessments of depressive symptoms mid-pregnancy, three years postpartum, ten years postpartum and during brain scans. The neuroimaging scan was performed 15 years after birth, when the participants were about 47 years old on average.
“In this study, we identified weak to no associations between trajectories of depressive symptoms and midlife brain health,” the researchers told PsyPost. They analyzed brain health markers such as gray and white matter volume, white matter lesions, cerebral microbleeds and subcortical structures.
“This finding contrasted a study that focused on late life instead, which found associations between depression symptoms and brain health. Therefore, the take-away here would be that changes in depression symptoms may not have a large impact on brain health in middle age, but that this the relationship may only become prominent later in life.”
Luik and Schuurmans also highlighted a finding that was particularly surprising.
“We found that participants with low but increasing depressive symptoms over time had more cortical thickening in a small brain region in the lateral occipital cortex,” they explained. “This finding was unexpected, as in contrast to previous depression literature, we found more rather than less cortical thickness.”
“In addition, the region was involved in the response to visual shape information and the processing of objects, which is not a typical characteristic of depression. Together, this may mean that visual processing is increased in those with more depressive symptoms, but more research should be conducted to ensure that this The finding was not an accidental discovery.”
The study, like all research, includes some caveats.
“The first measurement of depressive symptoms took place when our participants were expecting a child. Although pregnancy is generally considered a positive life event, women also experience reduced physical health and more depressive symptoms during this period,” said Luik and Schuurmans.
“It is therefore possible that the measurement of depressive symptoms in this period was more severe due to the pregnancy. More research is needed to understand whether depressive symptoms during pregnancy have a different effect on brain health than depressive symptoms at other times in life.”
The study, “10-year trajectories of depressive symptoms and subsequent brain health in middle-aged adults,” was written by Isabel K. Schuurmans, Sander Lamballais, Runyu Zou, Ryan L. Muetzel, Manon HJ Hillegers, Charlotte AM Cecil and Annemarie I. Luik.