Perceived stress mediates the association between orbitofrontal cortex grey matter volume and depressive symptoms in older women

As a common mental health problem among elderly women, depressive symptoms can lead to serious consequences. Consistent evidence has demonstrated that perceived stress, an individual's subjective feelings and psychological responses to life events, is a stable risk factor for depressive symptoms in the elderly. However, little is known about the neurobiological correlates of perceived stress and the brain-stress mechanisms to predict depressive symptoms in the older population. In the research reported here, we used a voxel-based morphometry method based on structural magnetic resonance imaging to calculate grey matter volume (GMV) in the brain to study these issues in 120 older women. Whole-brain correlation analyses and predictive analyses showed that greater GMV in the right orbitofrontal cortex (OFC) was consistently associated with higher levels of perceived stress. Mediation analyses further indicated that perceived stress mediated the linkage of right OFC GMV to depressive symptoms. Importantly, these results remained even after adjusting for anxiety symptoms, showing a nature of specificity. Overall, our study may identify a new neuroanatomical marker of perceived stress in older women and suggest a potential neuropsychological pathway for the prediction of depressive symptoms in the elderly, in which the right OFC GMV is associated with depressive symptoms through perceived stress.