Unipolar Depression and Bipolar Depression Manifest Different Brain Abnormalities: A Voxel-based Morphometry Study

Background:Patients with bipolar depression is often misdiagnosed to be as unipolar depression due to the phenotype similarity of these two diseases. We hypothesize that patients with these two diseases may demonstrate difference in terms of gray matter volume. Methods:Structural magnetic resonance imaging (MRI) data were acquired from 64 subjects, including 17 unipolar depression patients, 19 bipolar depression patients and 28 healthy controls. Image preprocess were conducted using Voxel-based morphometry (VBM). Then the gray matter volume changes were compared among different groups. Results: Compared to healthy controls, both Unipolar and bipolar patients demonstrated significantly decreased gray matter volume in the right anterior cerebellum lobe. Moreover, we observed significant right superior temporal gyrus volume decrease in unipolar patients compared to both healthy controls and bipolar subjects. Conclusion: Our results indicated that volume changes in anterior cerebellum lobe could be used for the diagnosis of both unipolar and bipolar depressions. Additionally, the right superior temporal gyrus volume variations may differ in unipolar and bipolar patients and thereby could be used as a marker for differentiating these two diseases