Altered frontal and occipital cortical microstructure in obsessive-compulsive disorder - a multisite mega-analysis

Area of Science:

• Neuroimaging
• Neuropsychiatry
• Human Brain Imaging

Background:

• Cortical morphology alterations are known in obsessive-compulsive disorder (OCD).
• Intracortical myelination and its relation to cortical microstructure in OCD are underexplored.
• Gray/white matter contrast (GWC) on T1-weighted MRI is a potential marker for intracortical myelination.

Purpose of the Study:

• To investigate intracortical myelination differences in OCD using GWC.
• To examine the relationship between GWC, gray matter macrostructure (RVI), and OCD.
• To explore associations between GWC and clinical/demographic factors in OCD.

Main Methods:

• Compared GWC patterns using independent component analysis in 454 adults with OCD and 394 healthy controls across eight international sites.
• Assessed GWC association with the Regional Vulnerability Index (RVI) derived from ENIGMA-OCD gray matter morphology.
• Investigated GWC correlations with demographic and clinical variables in the OCD group.

Main Results:

• Individuals with OCD exhibited significantly higher GWC in occipital and frontal regions compared to controls.
• Elevated OCD RVI in individuals with OCD correlated with widespread increases in GWC.
• Higher GWC in frontal regions was associated with sexual/religious OCD symptoms.

Conclusions:

• This study provides novel evidence of cortical microstructural alterations in OCD.
• Cortical microstructural changes (GWC) are linked to both gray matter macrostructure and clinical presentation in OCD.
• GWC serves as a promising neuroimaging marker for exploring cortical pathophysiology in OCD.