Prognosis of schizophrenia subtypes

The evidence that each of the 'classic' subtypes of schizophrenia is associated with a characteristic patterns of course is generally weak but surprisingly good for some of the subtypes. Thus, consistent differences have been reported between paranoid, hebephrenic, and undifferentiated schizophrenia (diagnosed according to DSM-III) on a long-term follow-up of 19 years.(52) Paranoid schizophrenia tended to have a remittent course, and to be associated with less disability, in contrast to hebephrenia which had an insidious onset and poor long-term prognosis. Undifferentiated schizophrenia occupied an intermediate position. In the WHO International Pilot Study of Schizophrenia,(33) four alternative groupings of the ICD-9 subtypes were tested by a discriminant function for differences with regard to six course and outcome measures. Clear discrimination was achieved between simple and hebephrenic schizophrenia grouped together on the one hand and the schizoaffective subtype on the other. However, the comparison of simple and hebephrenic schizophrenia with paranoid schizophrenia resulted in a considerable degree of overlap.

Better discrimination has been claimed for groups of patients diagnosed according to the criteria of Leonhard. (53> A 5- to 13-year follow-up of 178 patients admitted with a diagnosis of schizophrenia and rediagnosed according to the Leonhardian criteria as systematic schizophrenia, atypical (unsystematic) schizophrenia, cycloid psychosis, or reactive psychosis(54) resulted in marked outcome differences on blind assessment. While only 10 per cent of the cases in the two schizophrenia groups were judged to have 'recovered', the corresponding proportion in the cycloid and reactive psychoses group was 38 per cent. Conversely, the proportions of 'unimproved' cases were 49 per cent and 3 per cent.

The question of whether good-prognosis remitting schizophrenia of an acute onset is a separate subtype that could also be distinguished symptomatologically was addressed in the WHO 10-country study(38) by comparing 274 patients with an initial ICD-9 diagnosis of acute schizophrenic episode and 752 patients with other schizophrenia subtypes. The group of acute cases tended to be younger and had a lower male-to-female ratio, but was no different from the rest of the schizophrenic patients with regard to initial symptomatology. Similar conclusions were reached by Vaillant(55) in a 4- to16-year follow-up of schizophrenic patients who remitted after an acute episode. This argues against acute schizophreniform illness being a discrete syndrome, outside the clinical spectrum of schizophrenia.

The course and outcome data on schizoaffective disorders seem to support their placement within the broad category of schizophrenia. A retrospective and prospective study of 150 schizoaffective patients and 95 bipolar affective patients (56) established general similarities between the two groups but the schizoaffective cases were less likely to achieve a full remission and more likely to develop a residual state (in 57 per cent compared to 24 per cent for the bipolar group). An intermediate outcome between that of schizophrenia and bipolar affective disorder is a common finding.(22) Predictors of course and outcome

A wide range of variables have been explored as possible predictors of course and outcome in schizophrenia: sociodemographic characteristics; characteristics of the premorbid personality and pre-onset functioning; family history of psychiatric disorder; history of past psychotic episodes and treatments; substance use; characteristics of the onset; features of the initial clinical state and treatment response; variables related to brain morphology and neurocognitive functioning. A synopsis of findings about predictors is presented in Tabl§ 3.. I§ble...4 lists the results of statistical analysis of predictors for each of four different measures of 2-year course and outcome in the WHO 10-country study.(38)

Table 3 Significant findings about predictors of course and outcome in schizophrenia

Table 4 Best predictors of 2-year course and outcome in the WHO 10-country study (results of log-linear analysis of 1078 cases)

Many predictors have been replicated independently by different investigators and there is reasonable agreement on the general direction of their effects. However, the definitions of both the independent (predictor) and the dependent (outcome) variable vary across studies, and the statistical methods employed range from simple descriptive statistics (e.g. x per cent of the patients with characteristic y developed outcome z) to proper statistical models with capacity to quantify the independent contribution of individual variables to a specified outcome.

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Responses

  • edward
    Which subtypes of schizophrenia have a poor prognosis?
    20 days ago

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