Schizoaffective psychoses: Genetical clues to classification

Department of Psychiatric Demography, Aarhus University Psychiatric Hospital, Denmark.
American Journal of Medical Genetics (Impact Factor: 3.23). 02/1995; 60(1):7-11. DOI: 10.1002/ajmg.1320600103
Source: PubMed

ABSTRACT The diagnostic classification of schizoaffective psychoses has varied much since Kasanin introduced the concept in 1933. The various classifications have agreed that schizoaffective psychoses present a combination of schizophreniform and affective symptoms, but the diagnostic criteria differ as to the number, quality, and time sequence of the symptoms even in recent classifications like RDC, DSM-III-R, and ICD-10. The classifications are syndromatical, and the etiology of the schizoaffective psychoses is still undetermined apart from evidence for a strong genetic factor. Results from family, twin, and adoption studies are divergent, but all the same, support a separate classification of broadly defined schizoaffective psychoses as possibly being phenotypical variations or expressions of genetic interforms between schizophrenia and affective psychoses.

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    ABSTRACT: There is substantial evidence for partial overlap of genetic influences on schizophrenia and bipolar disorder, with family, twin, and adoption studies showing a genetic correlation between the disorders of around 0.6. Results of genome-wide association studies are consistent with commonly occurring genetic risk variants, contributing to both the shared and nonshared aspects, while studies of large, rare chromosomal structural variants, particularly copy number variants, show a stronger influence on schizophrenia than bipolar disorder to date. Schizoaffective disorder has been less investigated but shows substantial familial overlap with both schizophrenia and bipolar disorder. A twin analysis is consistent with genetic influences on schizoaffective episodes being entirely shared with genetic influences on schizophrenic and manic episodes, while association studies suggest the possibility of some relatively specific genetic influences on broadly defined schizoaffective disorder, bipolar subtype. Further insights into genetic relationships between these disorders are expected as studies continue to increase in sample size and in technical and analytical sophistication, information on phenotypes beyond clinical diagnoses are increasingly incorporated, and approaches such as next-generation sequencing identify additional types of genetic risk variant.
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    ABSTRACT: Brain structural changes in schizoaffective disorder, and how far they resemble those seen in schizophrenia and bipolar disorder, have only been studied to a limited extent. Forty-five patients meeting DSM-IV and RDC criteria for schizoaffective disorder, groups of patients with 45 matched schizophrenia and bipolar disorder, and 45 matched healthy controls were examined using voxel-based morphometry (VBM). Analyses comparing each patient group with the healthy control subjects found that the patients with schizoaffective disorder and the patients with schizophrenia showed widespread and overlapping areas of significant volume reduction, but the patients with bipolar disorder did not. A subsequent analysis compared the combined group of patients with the controls followed by extraction of clusters. In regions where the patients differed significantly from the controls, no significant differences in mean volume between patients with schizoaffective disorder and patients with schizophrenia in any of five regions of volume reduction were found, but mean volumes in the patients with bipolar disorder were significantly smaller in three of five. The findings provide evidence that, in terms of structural gray matter brain abnormality, schizoaffective disorder resembles schizophrenia more than bipolar disorder. © 2015 The Authors. Acta Psychiatrica Scandinavica Published by John Wiley & Sons Ltd.
    Acta Psychiatrica Scandinavica 05/2015; DOI:10.1111/acps.12440 · 5.55 Impact Factor


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Sep 24, 2014