Associations between subclinical depressive symptoms and reduced brain volume in middle-aged to older adults

ABSTRACT

Objectives: The associations between subclinical depressive symptoms, as well specific symptom subscales, on brain structure in aging are not completely elucidated. This study investigated the extent to which depressive symptoms were related to brain volumes in fronto-limbic structures in a sample of middle-aged to older adults.

Method: Eighty participants underwent structural neuroimaging and completed the Beck Depression Inventory, 2nd Edition (BDI-II), which comprises separate affective, cognitive, and somatic subscales. Gray matter volumes were extracted from the caudal and rostral anterior cingulate, posterior cingulate, hippocampus, and amygdala. Hierarchical regression models examined the relationship between brain volumes and (i) total depressive symptoms and (ii) BDI-II subscales were conducted.

Results: After adjusting for total intracranial volume, race, and age, higher total depressive symptoms were associated with smaller hippocampal volume (p = 0.005). For the symptom subscales, after controlling for the abovementioned covariates and the influence of the other symptom subscales, more somatic symptoms were related to smaller posterior cingulate (p = 0.025) and hippocampal (p < 0.001) volumes. In contrast, the affective and cognitive subscales were not associated with brain volumes in any regions of interest.

Conclusion: Our data showed that greater symptomatology was associated with smaller volume in limbic brain regions. These findings provide evidence for preclinical biological markers of major depression and specifically advance knowledge of the relationship between subclinical depressive symptoms and brain volume. Importantly, we observed variations by specific depressive symptom subscales, suggesting a symptom-differential relationship between subclinical depression and brain volume alterations in middle-aged and older individuals.

KEYWORDS:

• Aging
• BDI-II
• MRI
• somatic symptoms
• symptom dimensions

Acknowledgments

This work was supported by the McKnight Brain Research Foundation; the Center for Cognitive Aging and Memory at the University of Florida, and the National Institute on Aging, under Grants T32AG020499-11, R01AG054077-01, and K01AG050707-A101; the National Center for Advancing Translational Science under Grants UL1TR000064 and KL2TR000065; the National Institute of Mental Health, under Grant R03MH109336-02; the National Institute on Alcohol Abuse and Alcoholism, under Grants P01AA19072-07 and U01AA020797-06; and the National Institute of Diabetes and Digestive and Kidney Diseases, under Grant R01DK099334-03. Neuroimaging was performed at the Advanced Magnetic Resonance Imaging and Spectroscopy (AMRIS) facility in the McKnight Brain Institute of the University of Florida, which is supported by National Science Foundation Cooperative Agreement No. DMR-1157490 and the State of Florida.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

McKnight Brain Research Foundation; Center for Cognitive Aging and Memory at the University of Florida; National Institute on Aging [grant number T32AG020499-11], [grant number R01AG054077-01], [grant number K01AG050707-A101]; National Center for Advancing Translational Science [grant number UL1TR000064], [grant number KL2TR000065]; National Institute of Mental Health [grant number R03MH109336-02]; National Institute on Alcohol Abuse and Alcoholism [grant number P01AA19072-07], [grant number U01AA020797-06]; National Institute of Diabetes and Digestive and Kidney Diseases [grant number R01DK099334-03].