Abstract
Earlier structured MRI studies using manual tracing methods provided evidence of brain abnormalities in depressive disorder and bipolar disorder, and the latest MRI studies for these disorders have used voxel-based morphometry and FreeSurfer software for image analysis of large samples. These findings suggest that patients with depressive disorder and bipolar disorder show small gray matter volumes for the anterior cingulate and insula, both relevant to mood regulation. Familial MRI studies of these disorders have also shown reduced gray matter volumes in these regions. Diffusion tensor imaging studies have demonstrated abnormal white matter integrity for the genu corpus callosum near the anterior cingulate in patients with the two disorders. Future studies are necessary to elucidate the pathophysiologies of depressive and bipolar disorder and to address their diagnostic and treatment biomarkers.
