Relationship between illness duration, corpus callosum changes, and sustained attention dysfunction in major...

Area of Science:

• Neuroimaging
• Neuroscience
• Psychiatry

Background:

• Illness duration is a key indicator of depression severity.
• Corpus callosum (CC) damage is a consistent finding in major depressive disorder (MDD).
• The relationship between illness duration and CC alterations requires further investigation.

Purpose of the Study:

• To investigate the association between illness duration and CC structural and functional changes in MDD.
• To explore how CC alterations mediate the relationship between illness duration and clinical symptoms.

Main Methods:

• Diffusion and resting-state fMRI were used in 96 MDD patients and 50 controls.
• White matter microstructure (FA) and inter-hemispheric connectivity (VMHC) of CC sub-regions were quantified.
• Correlation and mediation analyses examined associations between illness duration, CC changes, and clinical variables.

Main Results:

• Longer illness duration correlated with reduced FA in CC sub-regions 2 and 5.
• Increased VMHC was observed in areas connected by affected CC sub-regions, including supplementary motor areas, precuneus, and lingual gyrus.
• Reduced FA in CC sub-regions 2 and 5 mediated the link between longer illness duration and sustained attention deficits.

Conclusions:

• Increasing depression illness duration is associated with compromised CC structure and compensatory functional changes.
• These findings suggest distinct neurobiological impacts of depression chronicity.
• Understanding these CC changes may guide tailored antidepressant treatment strategies.