Obsessive-compulsive disorder spectrum as a scientific "metaphor"

Area of Science:

• Neuroscience
• Psychiatry
• Genetics

Background:

• Obsessive-compulsive disorder (OCD) is well-characterized within anxiety disorders.
• Other disorders with similar features have been grouped around OCD, forming a conceptual cluster known as obsessive-compulsive related disorders (OCRDs).
• This 'OCRDs metaphor' has been valuable for exploring basal ganglia dysfunction.

Purpose of the Study:

• To review the current understanding and ongoing debates surrounding the obsessive-compulsive disorder spectrum.
• To highlight the need for further research to clarify the classification and characteristics of OCRDs.
• To emphasize the integration of biological and psychological perspectives for advancing the field.

Main Methods:

• Review of clinical, epidemiological, neuroimaging, and therapy studies.
• Analysis of shared phenomenology, comorbidities, course, demographics, genetics, and neuroimaging findings in OCRDs.
• Discussion of ongoing controversies and future research directions.

Main Results:

• OCRDs share significant commonalities, including frontostriatal dysfunction (e.g., caudate hyperactivity).
• Despite the utility of the OCRDs metaphor, the spectrum's boundaries and OCD's classification (unitary vs. split, anxiety disorder status) remain controversial.
• Existing research highlights the need for better definition of symptoms, subtypes, and endophenotypes.

Conclusions:

• Further research is essential to refine the conceptualization of the OCD spectrum.
• Integrating diverse data (biological, psychological) and improving endophenotyping protocols are crucial.
• Advancing research will help evolve the OCRD concept from a metaphor to a more structured framework.