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?

Comparative Analysis of DSM-5-TR and ICD-11 for Unspecified Schizophrenia Spectrum Disorders

Both DSM-5-TR and ICD-11 share fundamental weaknesses as categorical, symptom-based systems that lack neurobiological grounding, but ICD-11 demonstrates measurably superior clinical utility through its dimensional symptom specifiers and enhanced course descriptors, making it the preferred system for diagnosing unspecified psychotic presentations. 1

Shared Strengths of Both Systems

Clinical Communication and Reliability

• Both systems improved diagnostic reliability and reduced ambiguity in communication among clinicians, patients, and families compared to their predecessors 2
• The American Psychiatric Association and World Health Organization collaborated to harmonize DSM-5 and ICD-11, moving both toward dimensional assessment and away from discrete subtypes 1, 3
• Both systems are useful for education, training, reimbursement, and insurance purposes 2

Structural Improvements

• Both eliminated classical schizophrenia subtypes (paranoid, catatonic, disorganized) and reduced emphasis on Schneider's first-rank symptoms 4, 5
• Both systems now group psychotic disorders together in dedicated chapters with more coherent organizational structure 1

Shared Weaknesses of Both Systems

Fundamental Conceptual Limitations

• Both remain categorical at their core, classifying mental phenomena based on self-reported or clinically observable symptoms rather than underlying pathophysiology or neurobiology 6, 7
• Neither system is based on neurobiology despite large biological heterogeneity within diagnostic categories and difficulties distinguishing categories genetically and neurobiologically 6
• Changes from previous versions were relatively modest despite efforts toward dimensionality 7

Clinical and Prognostic Issues

• The schizophrenia construct does not recognize heterogeneity and may nourish the belief that it represents a unitary disease 2
• No agreement exists on the existence or nature of a "core aspect" of psychotic disorders 2
• Stable dimensions like negative symptoms and cognitive impairment, which are key determinants of functioning, are not regarded as core aspects de facto 2
• The construct is associated with notions of poor outcome, high stigma, and has acquired derogatory connotations 2

ICD-11 Specific Strengths

Superior 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, 7
• 82.5% to 83.9% of clinicians rated ICD-11 as quite or extremely easy to use, accurate, clear, and understandable 3, 7
• ICD-11 demonstrates superior clinical utility with measurably higher diagnostic accuracy and ease of use compared to both ICD-10 and DSM-5-TR 1

Dimensional Assessment Innovation

• 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" 1, 3
• This dimensional approach allows clinicians to complement categorical diagnoses with detailed symptom profiles that inform treatment planning beyond simple diagnostic labels 1
• Dimensional profiles provide more nuanced information for contexts where detailed assessment is needed to inform psychotherapy selection and intensity 3

Enhanced 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) 1, 7
• This enables more nuanced longitudinal understanding of illness patterns and captures temporal dynamics beyond categorical diagnosis 7
• The system allows rating symptom severity across multiple domains at each assessment, providing flexibility for treatment planning without requiring precise temporal calculations 7

Structural Reorganization

• ICD-11 introduced transsectional diagnostic criteria for schizoaffective disorder, representing a fundamental reorganization of how the diagnosis is conceptualized 7, 4
• Restriction of "Acute and Transient Psychotic Disorder" to more specific criteria improves diagnostic precision 5
• Formulation of a distinct subchapter for catatonia allows assessment of catatonic features across multiple disorders 5

ICD-11 Specific Weaknesses

Limited Evidence Base

• Advantages 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 7
• Field study samples could be biased toward practitioners positive about ICD-11, as online participants registered on their own initiative 7
• Vignette studies describe prototypic cases that might not accurately reflect the complexity of real-life situations 7
• Further ecological field studies are needed to reveal how well ICD-11 works when applied by clinical practitioners under regular conditions 7

Persistent Conceptual Gaps

• Developmental aspects remain unattended in ICD-11 definitions of psychotic disorders 5
• Despite dimensional additions, the system remains fundamentally categorical 7

DSM-5-TR Specific Characteristics

Dimensional Elements

• DSM-5 replaced schizophrenia subtypes with a dimensional approach based on symptom assessments 4
• However, dimensional assessment is less comprehensive than ICD-11's six-domain system 1

Structural Differences

• Different criteria for some disorders compared to ICD-11, particularly in the structure of corresponding sections 8
• Less emphasis on course specifiers and longitudinal characterization compared to ICD-11 1

Critical Pitfalls and Clinical Recommendations

Avoid Relying on Unstructured Assessment

• 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 1, 3
• Gather collateral information from family members and other observers, as patient insight may be limited during acute psychotic episodes 3, 7

Adopt Stepwise Diagnostic Approach

• Use a stepwise 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 for treatment planning and research 6, 1
• Create detailed life charts documenting the longitudinal course of symptoms to accurately determine temporal patterns 3, 7
• Plan for longitudinal reassessment, as the diagnosis frequently evolves over time and may require reclassification as more information becomes available 3, 7

Complement Categorical Diagnosis

• Clinicians should complement the ICD/DSM diagnosis with in-depth characterization of the individual clinical picture, along with family history, comorbidities, vulnerability factors, and personal trajectory 2
• Use dimensional ratings across all six symptom domains at each assessment to inform treatment selection 1, 3

Future Directions

• Develop trauma-informed specifiers with dimensional ratings for dissociative symptoms, re-experiencing phenomena, and hyperarousal to improve diagnostic precision for trauma-exposed populations 1, 3
• Consider biologically-defined subgroups within existing diagnostic categories, such as the Systems Neuroscience of Psychosis approach that links clinical manifestations onto specific brain systems 6, 1