Voxel-based morphometry study of the insular cortex in female patients with current and remitted depression

Women are more prone to major depressive disorders (MDDs) and the incidence of MDD in women is almost twice that of men. Insular cortex abnormalities are a common finding in neuroanatomical studies of patients with MDD. However, it remains largely unclear whether female MDD patients at different clinical stages show morphologic changes in a specific subregion of the insular cortex. Additionally, it is not understood if any subregion changes can be used as a state or trait marker of MDD, and whether the diagnostic performance of any marker is sufficient to identify MDD.

Nineteen right-handed current MDD (cMDD) female patients and 19 remitted MDD (rMDD) patients, as well as 19 healthy controls matched for age and educational level, were recruited into the study. By means of voxel-based morphometry (VBM), we investigated gray matter volume abnormalities in insular subregions among the three groups and further conducted region-of-interest (ROI)-based receiver operating characteristic (ROC) analyses. The data from these investigations were correlated with clinical data to confirm the effectiveness of the identified changes in the subregions in differentiating the three groups.

Both the cMDD and rMDD groups showed significantly decreased gray matter volumes in the left dorsal anterior insula compared to the healthy controls. The cMDD groups also showed decreased gray matter volumes in the right dorsal anterior insula relative to healthy controls. Further ROC comparisons demonstrated that the left dorsal anterior insula can effectively differentiate cMDD and rMDD groups from healthy controls.

Our findings suggest that the volume changes in the left dorsal anterior insular cortex may be a trait-related marker of vulnerability to MDD and that the right dorsal anterior insular cortex may involve pathological changes of MDD.