Functional and anatomical brain deficits in drug-naive major depressive disorder

Functional and anatomical deficits have been involved in the neurobiology of major depressive disorder (MDD). However, no study has ever been conducted to examine whether and how functional alterations are related to anatomical deficits in MDD. This study aimed to determine the association between brain functional and anatomical deficits in drug-naive MDD. Forty-four patients with MDD and 44 age-, sex-, and education-matched healthy controls underwent structural and resting-state functional magnetic resonance imaging scanning. The voxel-based morphometry (VBM) and amplitude of low-frequency fluctuation (ALFF) methods were used to analyze the imaging data. VBM analysis showed gray matter volume (GMV) reductions in the parietal–temporal regions (i.e., the right inferior temporal gyrus and the left angular gyrus). Functional alterations revealed by ALFF mainly occurred in the temporal regions (i.e., the left middle temporal gyrus and the right superior temporal gyrus) and the cerebellum (i.e., the culmen). There is no overlap between brain regions with functional alterations and anatomical deficits in the patients and their subgroups (first-episode depression and recurrent depression). The episode number and the illness duration were correlated with the mean GMV values of the left angular gyrus. A dissociation pattern of brain functional and anatomical deficits is observed in MDD. Our findings suggest that brain functional and anatomical deficits contribute independently to the neurobiology of MDD.