What are the strengths and weaknesses of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM‑5‑TR) and the International Classification of Diseases, Eleventh Revision (ICD‑11) for diagnosing obsessive‑compulsive disorder?

Comparative Strengths and Weaknesses of DSM-5-TR and ICD-11 for Diagnosing OCD

Both DSM-5-TR and ICD-11 share core diagnostic strengths by emphasizing obsessions and/or compulsions with clinical significance criteria, but DSM-5-TR provides superior clinical utility through more detailed insight specifiers and a tic-related specifier that guide treatment decisions, while ICD-11 offers greater diagnostic flexibility by removing arbitrary duration requirements and eliminating problematic diagnostic hierarchy exclusions.

Shared Strengths of Both Systems

Core Diagnostic Framework

• Both DSM-5-TR and ICD-11 correctly emphasize that OCD diagnosis requires the presence of obsessions and/or compulsions (not necessarily both), which accurately reflects the clinical heterogeneity of the disorder 1.
• Both systems appropriately include a clinical significance criterion requiring that symptoms cause clinically significant distress or functional impairment, which is essential given that intrusive thoughts and repetitive behaviors are common in the general population and rituals are normal developmental phenomena 1, 2.
• Both classification systems include diagnostic hierarchy criteria stating that obsessions and compulsions cannot be better explained by another mental disorder, substance effects, or medical condition, which helps prevent misdiagnosis 1.

Recognition of Symptom Dimensions

• Both systems acknowledge that obsessions and compulsions fall into a small number of stable symptom dimensions within individuals, with changes typically occurring within rather than across dimensions 1.

DSM-5-TR Specific Strengths

Enhanced Clinical Specifiers

• DSM-5-TR provides three detailed insight specifiers (good or fair insight, poor insight, and absent insight/delusional beliefs) that are critical for treatment planning and preventing misdiagnosis of OCD with absent insight as a psychotic disorder 1, 2.
• The tic specifier in DSM-5-TR (denoting current or past tic disorder) reflects growing evidence that patients with OCD with or without tics differ in phenomenology and psychobiology, which has treatment implications 1.

Refined Diagnostic Definitions

• DSM-5-TR redefined obsessions to better clarify that they can be thoughts, images, or impulses/urges, and recognizes the importance of avoidance and thought stopping as strategies beyond compulsions 3.
• The system clarifies that compulsions can be behaviors or mental acts performed in response to obsessions or according to rigid rules 2, 4.

Structured Assessment Integration

• DSM-5-TR has well-validated structured diagnostic interviews (SCID-5) and symptom severity measures (Y-BOCS) that are widely used and have strong psychometric properties 1, 2.

DSM-5-TR Specific Weaknesses

Categorical Rigidity

• The DSM-5-TR maintains relatively rigid categorical boundaries that may not capture the dimensional nature of OCD symptoms as effectively as needed for personalized treatment 5.
• The system's emphasis on discrete categories can make it challenging to capture subsyndromal presentations that may still require intervention 6.

ICD-11 Specific Strengths

Improved Diagnostic Flexibility

• ICD-11 removes the arbitrary 2-week duration requirement present in ICD-10, which inappropriately delayed diagnosis and treatment initiation 6.
• ICD-11 no longer excludes OCD diagnosis when comorbid with Tourette syndrome, schizophrenia, or depressive disorders, which better reflects clinical reality where these conditions frequently co-occur 6.

Global Applicability

• ICD-11 was designed with enhanced attention to global applicability and cross-cultural validity, making it more useful in diverse healthcare settings worldwide 6.

Convergence with Evidence-Based Classification

• ICD-11 moved OCD from anxiety disorders to its own category of Obsessive-Compulsive and Related Disorders, reflecting evidence of common affected neurocircuits rather than just symptom overlap 5.

ICD-11 Specific Weaknesses

Less Detailed Specifiers

• ICD-11 replaced the ICD-10 specifiers (predominantly obsessional thoughts, compulsive acts, or mixed) with only an insight specifier, which provides less granular clinical information than DSM-5-TR's multiple specifiers 6.
• The absence of a tic-related specifier in ICD-11 means it does not capture the important phenomenological and psychobiological differences between OCD with and without tics 1.

Limited Structured Assessment Tools

• ICD-11 has fewer well-validated structured diagnostic interviews and assessment instruments compared to DSM-5-TR, which may reduce diagnostic reliability in research and clinical settings 1, 2.

Critical Diagnostic Pitfalls Common to Both Systems

Distinguishing OCD from Normal Phenomena

• Both systems require clinicians to distinguish OCD from normal intrusive thoughts by assessing whether thoughts are time-consuming (>1 hour daily) and causing substantial distress or functional impairment 2, 7.
• The clinical significance threshold helps prevent overdiagnosis but requires careful clinical judgment about what constitutes "substantial" impairment 1, 2.

Differential Diagnosis Challenges

• Both systems require distinguishing OCD from generalized anxiety disorder and depression, where worries and ruminations are about real-life concerns and tend to be less irrational and ego-dystonic than OCD obsessions, and compulsions are typically absent 1, 7.
• Mental compulsions (mental reviewing, silent counting, praying, repeating words) are easily missed in both systems, leading to potential misdiagnosis as pure anxiety or depressive disorders 7.

Insight Assessment Complexity

• Both systems recognize that individuals with OCD and absent insight or delusional beliefs are convinced their OCD beliefs are true, creating risk for misdiagnosis as psychotic disorders if not properly assessed 1, 2.

Practical Clinical Implications

Assessment Approach

• Regardless of which system is used, comprehensive assessment requires detailed psychiatric history, mental status examination, and use of standardized instruments like the Y-BOCS (scores ≥14 indicate clinically significant OCD requiring treatment) 1, 2.
• Clinicians must specifically ask about mental compulsions and assess ego-dystonicity of thoughts to avoid missing OCD diagnoses 7.
• Family accommodation patterns (providing reassurance, assisting with avoidance, participating in rituals) should be assessed as these maintain symptoms 2.

Treatment Planning Impact

• The presence and degree of insight documented through either system's specifiers directly impacts treatment selection, as patients with poor or absent insight may require augmentation with antipsychotic medications 1.
• Documentation of tic-related features (more detailed in DSM-5-TR) influences treatment decisions, as this subtype may respond differently to interventions 1.