Brain structure and symptom dimension relationships in obsessive-compulsive disorder: a voxel-based morphometry...

Area of Science:

• Neuroimaging
• Neuroscience
• Psychiatry

Background:

• Obsessive-compulsive disorder (OCD) is a heterogeneous condition with stable symptom dimensions.
• Previous neuroimaging studies yielded inconsistent results, potentially due to symptom dimensions and clinical variables influencing gray matter (GM) volume.

Purpose of the Study:

• To investigate gray matter (GM) volume differences in adult patients with OCD compared to healthy controls.
• To explore the relationship between GM volume variations and clinical factors like symptom severity, age, and medication in OCD.

Main Methods:

• Voxel-based morphometry (VBM) was used to measure GM volume in 25 adult OCD patients and 20 healthy controls.
• Regression analyses examined associations between GM differences and age, age of onset, medication load, OCD severity, depression, and symptom dimensions.

Main Results:

• OCD patients showed reduced GM volume in dorsal cortical regions (e.g., BA6, BA46, BA9) and increased GM volume in the bilateral midbrain compared to controls.
• Greater OCD symptom severity correlated with smaller dorsal cortical GM volumes and larger bilateral midbrain GM volumes.
• Age and specific symptom dimensions (washing, hoarding) were also independently associated with GM volume variations in specific brain regions.

Conclusions:

• Structural neuroimaging reveals GM abnormalities in the dorsal prefrontal cortex and bilateral midbrain in OCD, primarily linked to overall symptom severity.
• These findings highlight the influence of clinical heterogeneity on neuroimaging results in OCD.
• Larger studies are needed to confirm the relationships between specific symptom dimensions and GM volumes.