Effects of illness duration and treatment resistance on grey matter abnormalities in major depression

Abstract

Background: Findings of brain structural changes in major depressive disorder are still inconsistent, partly because some crucial clinical variables have not been taken into account. Aims: To investigate the effect of major depressive disorder on grey matter volumes. Method: Voxel-based morphometry was used to compare 66 patients with depression at different illness stages (22 each with first-episode, remitted-recurrent and treatment resistant/chronic depression) with 32 healthy controls. Brain volumes were correlated with clinical variables. Results: Voxel-based morphometry showed a significant group effect in right superior frontal gyrus, left medial frontal gyrus and left cingulate gyrus (P<0.05, family wise error-corrected). Patients whose condition was treatment resistant/chronic exhibited the smallest volumes in frontotemporal areas. Longer illness duration was negatively correlated with decreases in right medial frontal cortex and left insula. Conclusions: Frontotemporolimbic areas are smaller in the patients with severe depression and are associated with duration of illness, but not with medication patterns, suggesting negative effects of long-lasting major depressive disorder on grey matter.