ICD-11 vs DSM-5: Diagnostic Requirements Comparison

Source: PMC/World Psychiatry Journal (First et al., 2021)

Overall Harmonization Success

Analysis of 103 comparable disorders reveals substantially improved alignment between classification systems:

• 31 (30.1%) have essentially identical definitions
• 10 (9.7%) differ only in DSM-5's greater operational specificity
• 42 (40.8%) show minor definitional differences
• 20 (19.4%) demonstrate major differences

Additionally, 26 disorders appear in only one system: 19 in ICD-11 alone, 7 in DSM-5 alone.

Organizational Structure Differences

The systems share similar groupings through dissociative disorders. Key structural divergences include:

• Catatonia: Separate ICD-11 grouping vs. DSM-5 specifier
• Somatic conditions: ICD-11 maintains separate categories; DSM-5 consolidates under one grouping
• Personality Disorders: ICD-11 uses dimensional traits; DSM-5 retains categorical approach
• Sexual health: ICD-11 Chapter 17; DSM-5 integrates within mental disorders

Major Conceptual Differences

Psychotic Disorders

• ICD-11 requires "1 month or more" symptom duration for schizophrenia
• DSM-5 demands "at least 6 months"
• ICD-11 separates "experiences of influence, passivity or control" from delusions
• DSM-5 categorizes these as delusional content

Mood Episodes

• ICD-11 maintains distinct mixed episodes
• DSM-5 applies a "mixed features" specifier to existing episode categories
• ICD-11 criteria address bereavement-related depression differently than DSM-5's approach

Trauma-Related Conditions

The systems diverge significantly on PTSD definition:

• ICD-11 distinguishes PTSD from Complex PTSD
• DSM-5 uses singular PTSD with broader symptom clustering
• ICD-11 broadens trauma types
• DSM-5 specifies narrower stressor criteria

Substance Use

• ICD-11 separates harmful use episodes from dependence
• DSM-5 employs severity gradations within unified Substance Use Disorder
• ICD-11 includes synthetic cannabinoids and cathinones as distinct classes

Personality Disorders

• ICD-11 implements dimensional trait approach with severity ratings
• DSM-5 maintains traditional categorical diagnoses with an alternative model in appendix

Paraphilic Disorders

• ICD-11 distinguishes non-consenting from consenting/solitary categories, reducing named diagnoses to decrease stigmatization
• DSM-5 retains specific paraphilia diagnoses

Minor Differences

Numerous disorders show subtle variations in symptom lists, duration thresholds, or operational definitions—particularly evident in:

• Anxiety disorders
• Tic disorders
• Eating disorders

These reflect differing empirical interpretations rather than fundamental conceptual disagreement.

Rationale for Divergence

Differences stem from organizational priorities:

• WHO (ICD-11): Emphasizes public health needs and global applicability
• APA (DSM-5): Applies stricter empirical evidence standards for diagnostic inclusion

These "genuinely different alternatives" create opportunities for comparative validity research.

Key Takeaway

The substantial harmonization achieved (over 80% with identical, minor, or specificity-only differences) represents significant progress toward unified global psychiatric classification while preserving each system's distinct strengths.