Gender-specific structural abnormalities in major depressive disorder revealed by fixel-based analysis

Area of Science:

• Neuroimaging
• Psychiatry
• Biomarker Discovery

Background:

• Major depressive disorder (MDD) is a significant global health burden.
• Current treatment outcome prediction for MDD lacks clinically useful biomarkers.
• Developing biomarkers is crucial for personalized antidepressant medication strategies.

Purpose of the Study:

• To identify novel diffusion MRI-based biomarkers for MDD diagnosis and treatment response.
• To explore gender-specific differences in brain structure related to MDD.
• To investigate the predictive value of brain imaging metrics for depression remission.

Main Methods:

• Fixel-based analysis of diffusion MRI data from 221 MDD patients and 67 healthy controls.
• Exploratory study within the International Study to Predict Optimized Treatment in Depression.
• Comparison of fixel-based analysis with conventional tensor-based metrics (fractional anisotropy).

Main Results:

• Identified gender-specific differences in the anterior internal capsule (males) and corpus callosum genu (females) associated with MDD diagnosis.
• Found reduced fiber cross-section in the tapetum linked to lower remission probability.
• Fixel-based analysis revealed distinct abnormalities compared to conventional metrics, with minimal overlap.

Conclusions:

• MDD is associated with distinct gender-specific white matter abnormalities in specific brain regions.
• Tapetum abnormalities predict treatment remission independently of gender.
• Diffusion MRI, particularly fixel-based analysis, shows promise for guiding clinical decisions in MDD management.