BackgroundA number of studies with conflicting results have examined the
familiality of schizophrenia syndromes in Western populations.AimsThe objective of this study was to determine, using clinical data from
concordant sibling pairs, whether symptom dimensions and other clinical
characteristics of schizophrenia show familial aggregation and are
therefore potentially useful traits in genetic studies.MethodWe measured clinical and demographic features, and symptom dimensions of
schizophrenia in 137 families from China who had two or more affected
members with schizophrenia. Within-sibling pair correlation was assessed
with intraclass correlation coefficient and kappa statistics.ResultsGlobal functioning, positive, disorganisation and dysphoric symptoms,
premorbid schizotypal and schizoid traits, premorbid social adjustment,
type and age at illness onset all showed significant evidence of familial
aggregation. DSM–IV schizophrenia subtypes were also found to be
familial.ConclusionsThis is the first study in a large non-European population to confirm
that schizophrenia dimensions and clinical characteristics show
significant familiality, implying possible heritability. This supports
their use in the delineation of homogeneous subsets for future genetic
studies.
Correlation and familial aggregation of dimensions of psychosis
in affected sibling pairs from China