What are the changes in diagnosis of other specified schizophrenia spectrum and other psychotic disorders across Diagnostic and Statistical Manual of Mental Disorders (DSM) versions 3, 3-TR (Text Revision), 4, 5, and 5-TR (Text Revision), and International Classification of Diseases (ICD) versions 10 and 11?

Evolution of "Other Specified Schizophrenia Spectrum and Other Psychotic Disorders" Across DSM and ICD Versions

The diagnostic category "Other Specified Schizophrenia Spectrum and Other Psychotic Disorders" represents a fundamental shift from earlier DSM versions, emerging as a formal category in DSM-5 to replace the DSM-IV "Psychotic Disorder Not Otherwise Specified" (NOS), while ICD-11 introduced dimensional symptom specifiers across six domains rated on a 4-point scale to enhance diagnostic precision beyond categorical labels. 1

Major Structural Changes Across Versions

DSM-III and DSM-IV Era

• DSM-III and DSM-IV utilized "Psychotic Disorder Not Otherwise Specified" (NOS) as a residual category for psychotic presentations that did not meet full criteria for specific disorders, with minimal guidance on subtyping or specification 1
• These earlier versions maintained purely categorical classification without dimensional assessment, limiting clinical utility for treatment planning 2

DSM-5 Revolution (2013)

• DSM-5 eliminated the NOS category and introduced "Other Specified Schizophrenia Spectrum and Other Psychotic Disorder," requiring clinicians to specify the reason the presentation does not meet criteria for a specific disorder 3
• The American Psychiatric Association shifted from purely categorical classification to a hybrid model incorporating dimensional symptom assessment, fundamentally changing diagnostic conceptualization 1
• DSM-5 eliminated traditional schizophrenia subtypes (paranoid, disorganized, catatonic, undifferentiated, residual) and replaced them with dimensional severity specifiers across multiple symptom domains 3, 4
• Schneiderian first-rank symptoms lost their special diagnostic status, no longer receiving preferential weight in diagnosis 3, 5

DSM-5-TR Continuity

• DSM-5-TR maintained the "Other Specified" framework introduced in DSM-5 without major structural changes to this category 1

ICD System Evolution

ICD-10 Approach

• ICD-10 utilized categories like "Other nonorganic psychotic disorders" and "Unspecified nonorganic psychosis" as residual categories, similar to DSM-IV's NOS approach 6
• ICD-10 maintained acute and transient psychotic disorders as distinct categories, providing more granular classification for brief psychotic presentations than DSM-IV 6

ICD-11 Transformation (2017-2022)

• ICD-11 restructured the entire mental disorders chapter, creating "Schizophrenia and Other Primary Psychotic Disorders" as a unified grouping with dimensional symptom specifiers across six domains: positive symptoms, negative symptoms, depressive symptoms, manic symptoms, psychomotor symptoms, and cognitive symptoms 2, 7
• Each symptom domain is rated on a 4-point scale from "not present" to "present and severe," allowing clinicians to create detailed symptom profiles that inform treatment planning beyond simple diagnostic labels 1, 7
• Field studies demonstrated that 82.5% to 83.9% of clinicians rated ICD-11 as quite or extremely easy to use, accurate, clear, and understandable, with higher reliability than ICD-10 for psychotic disorders 1, 2, 7

Harmonization Efforts Between DSM-5 and ICD-11

• The American Psychiatric Association and World Health Organization collaborated to ensure better alignment between DSM-5 and ICD-11, though conceptual differences remain, particularly in ICD-11's greater emphasis on dimensional assessment and global applicability 1, 7, 4
• Both systems moved toward dimensional approaches, but ICD-11 implemented this more comprehensively with its six-domain rating system 2, 6

Clinical Assessment Implications

Diagnostic Approach

• The American Academy of Child and Adolescent Psychiatry recommends using structured diagnostic interviews (such as SCID-5 or MINI 7.0) rather than unstructured clinical assessment to reduce diagnostic bias and improve reliability when evaluating any psychotic presentation 1, 7
• Clinicians should create detailed life charts documenting the longitudinal course of symptoms, as diagnosis frequently evolves over time 1, 2, 7
• Gathering collateral information from family members and other observers is crucial, as patient insight may be limited during acute psychotic episodes 7

Documentation Requirements

• When using "Other Specified" categories in DSM-5/5-TR, clinicians must document the specific reason the presentation does not meet criteria for a defined disorder (e.g., "persistent auditory hallucinations in the absence of any other features") 3
• ICD-11 requires rating symptom severity across all six domains and documenting episodicity and current status to capture the longitudinal pattern beyond the categorical diagnosis 2

Common Pitfalls and Caveats

• Neither DSM-5-TR nor ICD-11 has biological validation, resulting in biologically heterogeneous groups within the same diagnostic category, which limits the precision of "Other Specified" diagnoses 2
• The advantages of ICD-11's dimensional approach are most pronounced for new diagnostic categories; when excluding new categories, differences in diagnostic accuracy compared to ICD-10 were not significant 2
• Clinicians should plan for longitudinal reassessment, as patients often present during acute psychosis before meeting duration criteria for more specific diagnoses like schizophrenia (6-month requirement) 1, 2
• Complete recovery within 6 months is unusual for schizophrenia, as negative symptoms typically persist; this temporal pattern helps differentiate true brief psychotic episodes from early schizophrenia presentations 2