White matter alterations associate with onset symptom dimension in obsessive-compulsive disorder

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Obsessive-compulsive disorder (OCD) exhibits significant heterogeneity, often characterized by distinct symptom dimensions.
• Understanding the neurobiological underpinnings of these symptom dimensions is crucial for developing targeted treatments.

Purpose of the Study:

• To investigate white matter alterations in OCD patients, specifically examining the enduring impact of symptom dimensions identified at illness onset.
• To control for medication effects and current symptom dimensions when analyzing white matter changes.

Main Methods:

• Diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS) were employed.
• 58 OCD patients and 58 healthy controls were analyzed.
• Patients were subgrouped based on symptom dimensions at illness onset and current symptom dimensions using a five-factor model.

Main Results:

• Significant white matter alterations were observed in OCD patients, particularly associated with doubt/checking and rituals/superstition dimensions at onset, and symmetry/perfectionism currently.
• The association between current symmetry/perfectionism and white matter changes was evident only after accounting for the effect of onset doubt/checking.
• Observed differences between patients and controls were substantially influenced by current and previous medication use.

Conclusions:

• Symptom dimensions at OCD onset are associated with persistent white matter microstructure alterations, potentially reflecting underlying endophenotypes.
• Medication, particularly current treatment, significantly impacts white matter integrity, specifically affecting myelination in OCD.