Brain morphometric biomarkers distinguishing unipolar and bipolar depression. A voxel-based morphometry-pattern...

Area of Science:

• Neuroimaging
• Psychiatry
• Brain Anatomy

Background:

• Structural brain abnormalities differentiating unipolar depression (UD) and bipolar depression (BD) are not well-defined.
• Accurate differentiation is crucial for effective treatment strategies.

Purpose of the Study:

• To compare morphometric brain changes in UD and BD across two independent neuroimaging sites.
• To develop and validate a pattern classification method for distinguishing UD from BD.

Main Methods:

• A cross-sectional study involving 3-T magnetic resonance imaging (MRI) at two international sites (Pittsburgh and Münster).
• Voxel-based morphometry (VBM) was used to analyze gray and white matter volumes.
• Multivariate pattern classification was employed to discriminate between UD and BD groups.

Main Results:

• Individuals with BD exhibited reduced gray matter volume in the hippocampus and amygdala compared to those with UD.
• Individuals with UD showed reduced gray matter volume in the anterior cingulate gyrus compared to those with BD.
• Pattern classification achieved up to 79.3% accuracy in differentiating UD from BD, with cross-site validation yielding 69.0% accuracy.

Conclusions:

• Distinct structural abnormalities in emotion-processing neural regions differentiate UD and BD.
• Neuroimaging and pattern classification techniques show potential as diagnostic aids for distinguishing between UD and BD.