Psychotic Disorders in ICD-11

Catatonia in DSM-5

Although catatonia has historically been associated with schizophrenia and is listed as a subtype of the disorder, it can occur in patients with a primary mood disorder and in association with neurological diseases and other general medical conditions. Consequently, catatonia secondary to a general medical condition was included as a new condition and catatonia was added as an episode specifier of major mood disorders in DSM-IV. Different sets of criteria are utilized to diagnose catatonia in schizophrenia and primary mood disorders versus neurological/medical conditions in DSM-IV, however, and catatonia is a codable subtype of schizophrenia but a specifier for major mood disorders without coding. In part because of this discrepant treatment across the DSM-IV manual, catatonia is frequently not recognized by clinicians. Additionally, catatonia is known to occur in several conditions other than schizophrenia, major mood disorders, or secondary to a general medical condition. Four changes are therefore made in the treatment of catatonia in DSM-5. A single set of criteria will be utilized to diagnose catatonia across the diagnostic manual and catatonia will be a specifier for both schizophrenia and major mood disorders. Additionally, catatonia will also be a specifier for other psychotic disorders, including schizoaffective disorder, schizophreniform disorder, brief psychotic disorder, and substance-induced psychotic disorder. A new residual category of catatonia not otherwise specified will be added to allow for the rapid diagnosis and specific treatment of catatonia in severely ill patients for whom the underlying diagnosis is not immediately available. These changes should improve the consistent recognition of catatonia across the range of psychiatric disorders and facilitate its specific treatment.

Definition and description of schizophrenia in the DSM-5

Although dementia praecox or schizophrenia has been considered a unique disease for over a century, its definitions and boundaries have changed over this period and its etiology and pathophysiology remain elusive. Despite changing definitions, DSM-IV schizophrenia is reliably diagnosed, has fair validity and conveys useful clinical information. Therefore, the essence of the broad DSM-IV definition of schizophrenia is retained in DSM-5. The clinical manifestations are extremely diverse, however, with this heterogeneity being poorly explained by the DSM-IV clinical subtypes and course specifiers. Additionally, the boundaries of schizophrenia are imprecisely demarcated from schizoaffective disorder and other diagnostic categories and its special emphasis on Schneiderian "first-rank" symptoms appears misplaced. Changes in the definition of schizophrenia in DSM-5 seek to address these shortcomings and incorporate the new information about the nature of the disorder accumulated over the past two decades. Specific changes in its definition include elimination of the classic subtypes, addition of unique psychopathological dimensions, clarification of cross-sectional and longitudinal course specifiers, elimination of special treatment of Schneiderian 'first-rank symptoms', better delineation of schizophrenia from schizoaffective disorder, and clarification of the relationship of schizophrenia to catatonia. These changes should improve diagnosis and characterization of individuals with schizophrenia and facilitate measurement-based treatment and concurrently provide a more useful platform for research that will elucidate its nature and permit a more precise future delineation of the 'schizophrenias'.

Does change in definition of psychotic symptoms in diagnosis of schizophrenia in DSM-5 affect caseness?

Psychotic symptoms are a central element in the diagnosis of schizophrenia, although their precise definition has varied through the multiple iterations of DSM and the ICD. Schneiderian first-rank symptoms (FRS) have received a particularly prominent position in the diagnostic criteria of schizophrenia since ICD-9 and DSM-III. In the current iteration of DSM (DSM-IV-TR), whereas two characteristic symptoms are ordinarily required to meet criterion A, only a single symptom is necessary if the psychotic symptom happens to be a FRS, notably a bizarre delusion or auditory hallucination of a running commentary or 'conversing voices'. Because of limited data in support of the special treatment of FRS, DSM-5 has made changes to criterion A, requiring that at least two psychotic symptoms be present in all cases with at least one of these symptoms being a delusion, hallucination, or disorganized speech. To assess the impact of these changes on the prevalence of schizophrenia, we examined a research dataset of 221 individuals with DSM-IV schizophrenia to study the prevalence and co-occurrence of various criterion A symptoms. Although bizarre delusions and/or Schneiderian hallucinations were present in 124 patients (56.1%), they were singly determinative of diagnosis in only one patient (0.46%). Additionally, only three of the 221 patients (1.4%) with DSM-IV schizophrenia did not have a delusion, hallucination, or disorganized speech. DSM-5 changes in criteria A should have a negligible effect on the prevalence of schizophrenia, with over 98% of individuals with DSM-IV schizophrenia continuing to receive a DSM-5 diagnosis of schizophrenia in this dataset.