White matter microstructural abnormalities and their association with anticipatory anhedonia in depression

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• Anhedonia, a core symptom of major depressive disorder (MDD), is linked to reward circuitry dysfunction.
• The precise neurobiological underpinnings of anhedonia in MDD remain incompletely understood.
• White matter (WM) integrity may play a role in the pathophysiology of anhedonia.

Purpose of the Study:

• To investigate the association between white matter (WM) characteristics and anhedonia in patients with first-episode, drug-naive major depressive disorder (MDD).
• To explore correlations between specific WM microstructural changes and different facets of anhedonia.

Main Methods:

• Diffusion weighted imaging (DWI) and Track-Based Spatial Statistics (TBSS) were employed in 30 first-episode drug-naive MDD patients and 28 healthy controls (HC).
• Anhedonia was assessed using the Temporal Experience of Pleasure Scale (TEPS).
• Fractional anisotropy (FA) and radial diffusivity (RD) were analyzed in relation to anhedonia severity.

Main Results:

• MDD patients displayed reduced FA in the left cingulum and forceps minor.
• Increased RD was observed in multiple left-hemisphere tracts, including the anterior thalamic radiation, corticospinal tract, superior longitudinal fasciculus, and uncinate fasciculus.
• Increased RD correlated with anticipatory anhedonia in MDD, while reduced FA correlated with consummatory anhedonia in HC.

Conclusions:

• Preliminary findings suggest that abnormalities in left-sided white matter (WM) tracts are associated with anhedonia in first-episode major depressive disorder (MDD).
• These WM alterations may represent a neurobiological substrate contributing to the development or manifestation of anhedonia in MDD.