Course and subtypes of schizophrenia

Both ICD-10 and DSM-IV provide broadly similar classifications of longitudinal course. The subtypes of schizophrenia included in both ICD-10 and DSM-IV are paranoid, catatonic, undifferentiated and residual schizophrenia. Hebephrenic schizophrenia is called disorganized type in DSM-IV. The requirement for the subtypes is similar in both classification systems, although they are more clearly operationalized in DSM-IV.

Common subtypes in ICD-10 and DSM-IV

• Paranoid
• Catatonic
• Hebephrenic (disorganized in DSM-IV)
• Residual
• Undifferentiated

Additional subtypes in ICD-10

• Simple
• Postschizophrenic depression

ICD-10 also includes subcategories of simple schizophrenia and postschizophrenic depression as subtypes of schizophrenia.

ICD-10 clarifies retention of simple schizophrenia as a subtype of schizophrenia, with the requirement of certain described features for at least 2 years because of its continued use in some countries and because of the uncertainty about its nature, which will require additional information for resolution.

Table 1.4 DSM-IV diagnostic criteria for schizophrenia.
Characteristic symptoms
At least one of:
Bizarre delusions
Third person auditory hallucinations
Running commentary

or two or more of:
Delusions
Hallucinations
Disorganized speech
Grossly disorganized behaviour
Negative symptoms

Duration
1 month of characteristic symptoms
With 6 months of social/occupational dysfunction

Exclusion criteria
Schizoaffective or mood disorders
Direct consequence of substance use or general medical condition
Pervasive developmental disorders

Diagnosis of postpsychotic depression requires a clear diagnosis of schizophrenia within the past 12 months with the presence of some features of schizophrenia and predominant depressive symptoms, which meet a threshold of depressive episode, for 2 weeks.

In addition to a categorical description of schizophrenia subtypes, DSM-IV offers a dimensional alternative in its Appendix B:

• psychotic dimension;
• disorganized dimension; and