What are the strengths and weaknesses of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) and International Classification of Diseases, Eleventh Revision (ICD-11) in diagnosing unspecified schizophrenia spectrum and other psychotic disorders?

Diagnostic Classification Systems for Unspecified Schizophrenia Spectrum and Other Psychotic Disorders

Direct Answer

ICD-11 demonstrates superior clinical utility with measurably higher diagnostic accuracy and ease of use compared to both ICD-10 and DSM-5-TR for psychotic disorders, though both systems remain fundamentally categorical and symptom-based rather than pathophysiology-based. 1

Strengths of ICD-11

Dimensional Assessment Capabilities

• ICD-11 introduces dimensional symptom specifiers across six domains (positive symptoms, negative symptoms, depressive symptoms, manic symptoms, psychomotor symptoms, and cognitive symptoms) rated on a 4-point scale from "not present" to "present and severe," allowing clinicians to complement categorical diagnoses with detailed symptom profiles that inform treatment planning beyond simple diagnostic labels. 2

• The dimensional approach provides flexibility for treatment planning without requiring precise temporal calculations, particularly valuable for psychotherapy selection and intensity determination. 3

Course Specification

• ICD-11 added two-component course specifiers: episodicity (first episode, multiple episodes, or continuous course) and current clinical status (currently symptomatic, partial remission, full remission), enabling more nuanced longitudinal understanding of illness patterns. 2, 4

Field-Tested Clinical Utility

• Field studies with 873 clinicians demonstrated small but measurable improvements in diagnostic accuracy using ICD-11 compared to ICD-10 specifically for psychotic disorders. 1, 4

• Between 82.5% to 83.9% of clinicians rated ICD-11 as quite or extremely easy to use, accurate, clear, and understandable in ecological field studies. 2, 1, 3

• Interrater reliability was high for psychotic disorders in ICD-11 ecological field studies, representing improvement over previously reported ICD-10 estimates. 2

Strengths of DSM-5-TR

Elimination of Problematic Subtypes

• DSM-5 eliminated the classic subtypes of schizophrenia (paranoid, disorganized, catatonic, undifferentiated, residual), which lacked empirical support and had poor reliability, replacing them with a dimensional symptom assessment approach. 5, 6

• Removed special treatment of Schneiderian "first-rank symptoms," which were not specific to schizophrenia and did not predict course or treatment response. 5

Harmonization Efforts

• The American Psychiatric Association and World Health Organization collaborated to ensure better alignment between DSM-5 and ICD-11, moving both systems toward dimensional assessment and away from discrete subtypes. 1, 3, 4

Weaknesses of Both Systems

Fundamental Categorical Limitations

• Both ICD-11 and DSM-5-TR remain categorical at their core, classifying mental phenomena based on self-reported or clinically observable symptoms rather than underlying pathophysiology or neurobiology. 1

• Changes from previous versions were relatively modest despite efforts toward dimensionality, maintaining the traditional symptom-based approach that has persisted for over 100 years without elucidating illness mechanisms. 1, 6

Limited Evidence for Improvements

• Advantages of ICD-11 over ICD-10 were largely limited to new diagnostic categories; when excluding new categories, there was no significant difference in diagnostic accuracy, goodness of fit, clarity, or time required for diagnosis. 2, 1

• Field study samples could be biased toward practitioners positive about ICD-11, as online participants registered on their own initiative, potentially inflating perceived benefits. 2, 1

• Vignette studies describe prototypic cases that might not accurately reflect the complexity of real-life clinical situations. 1

Reliability Concerns

• While reliability was excellent for some diagnoses (social anxiety disorder), it remained improvable for others (dysthymic disorder), with utility ratings varying significantly between countries. 2

• For anxiety and fear-related disorders, interrater reliability was small in ecological field studies from Mexico. 2

Specific Improvements Needed

For Clinical Work

Implement structured diagnostic interviews (SCID-5 or MINI 7.0) rather than unstructured clinical assessment to reduce diagnostic bias and improve reliability when evaluating any psychotic presentation. 3, 4, 7

• Create detailed life charts documenting the longitudinal course of symptoms to accurately determine temporal relationships and episodicity patterns. 1, 3, 4

• Gather collateral information from family members and other observers systematically, as patient insight may be limited during acute psychotic episodes. 1, 3

• Plan for longitudinal reassessment with systematic life charting, as the diagnosis frequently evolves over time and may require reclassification as more information becomes available. 1, 3

For Research and Future Development

Adopt a stepwise diagnostic procedure where the first step identifies patients requiring specialized treatment using broad categories, the second step provides detailed differential diagnosis using current ICD-11 guidelines, and a third step incorporates dimensional assessments and biological markers for research contexts. 2

• Develop trauma-informed specifiers with dimensional ratings for dissociative symptoms, re-experiencing phenomena, and hyperarousal to improve diagnostic precision for trauma-exposed populations. 3

• Expand dimensional assessment to all psychotic disorder categories, including specific domains for trauma-related symptoms and substance use severity. 3

• Pursue biologically-defined subgroups within existing diagnostic categories, such as the Systems Neuroscience of Psychosis (SyNoPsis) approach that links clinical manifestations onto specific brain systems (language/associative loop, affect/limbic loop, motor behavior/motor loop). 2

Critical Caveats

• The connection between neurobiology and psychopathology is not sufficiently understood to establish a diagnostic system based on biological markers alone, making premature abandonment of symptom-based classification clinically impractical. 2

• Complex approaches like Research Domain Criteria (RDoC) are suitable for research contexts but lack the clinical utility needed for routine practice, where well-communicable, comprehensible diagnostic categories remain essential. 2

• Further ecological field studies are needed to reveal how well ICD-11 works when applied by clinical practitioners under regular conditions rather than controlled research settings. 1