the smaller sample size (n = 98) or it may be an indication that the RDC definition of schizoaffective disorder, bipolar type is more biologically useful than that of DSM–IV (at least with respect to identifying the contribution of common genetic variation to disease susceptibility). The RDC definition focuses on temporal co-occurrence of a major affective syndrome with specific types of psychotic features, whereas the focus of the DSM–IV definition is temporal separation of mood and psychotic symptomatology without reference to the quality of the psychotic features.
