Biomarkers of Obsessive-Compulsive Disorder Subtypes: A Literature Review.

Area of Science:

• Neuroscience
• Psychiatry
• Genetics

Background:

• Obsessive-compulsive disorder (OCD) is a complex mental illness with diverse clinical presentations.
• Identifying distinct OCD subtypes is crucial for understanding its neurobiology.
• Phenotypic manifestations of OCD suggest underlying heterogeneity.

Purpose of the Study:

• To systematically integrate multi-level biomarker data (genetic, neuroimaging, neuropsychological).
• To align biomarker data with consistently replicated, symptom-based OCD subtypes.
• To explore divergent neurobiological pathways across OCD subtypes.

Main Methods:

• Systematic literature review and data integration.
• Analysis of genetic, neuroimaging, and neuropsychological biomarkers.
• Alignment of biomarkers with established OCD symptom subtypes.

Main Results:

• Distinct OCD subtypes are associated with unique neurobiological pathways.
• Dysregulation in glutamatergic, serotonergic, dopaminergic, and neurotrophic systems identified.
• Specific patterns of brain region engagement differ between subtypes, notably contamination/cleaning and symmetry/ordering OCD.

Conclusions:

• Evidence supports distinct neurobiological underpinnings for OCD subtypes.
• The contamination/cleaning and symmetry/ordering subtypes have the most robust biomarker evidence.
• Further investigation is needed for other OCD subtypes to refine classification and guide future research.