White matter structure and symptom dimensions in obsessive-compulsive disorder

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• Obsessive-compulsive disorder (OCD) presents with diverse symptom dimensions.
• These dimensions may involve distinct neural systems.
• Understanding these distinct neural underpinnings is crucial for targeted treatments.

Purpose of the Study:

• To investigate the relationship between OCD symptom dimensions and white matter microstructure.
• To identify specific white matter alterations associated with distinct OCD symptom clusters.

Main Methods:

• Diffusion Tensor Imaging (DTI) was employed to analyze white matter microstructure.
• Fractional anisotropy (FA), axial diffusivity, and radial diffusivity were measured.
• Correlations were examined between DTI metrics and OCD symptom dimensions (obsessing, ordering).

Main Results:

• Obsessing symptom severity correlated negatively with FA in the corpus callosum and cingulate bundle.
• Ordering symptom severity correlated negatively with FA in the inferior fronto-occipital fasciculus and optic radiation.
• Observed correlations were primarily due to alterations in radial diffusivity, not axial diffusivity.

Conclusions:

• Distinct white matter alterations are associated with different OCD symptom dimensions.
• Obsessive thoughts link to changes in cognitive control and inhibition pathways.
• Ordering symptoms associate with alterations in visual processing tracts, impacting attention to detail.