Evaluation of familial influences onthe course and severity of schizophrenia among US and Indiancases

Abstract.Background: Prior studies suggest familial (possibly genetic)influences on the course of schizophrenia.Aims: The aim of this study was to compare familial influenceson the course and severity of schizophrenia in two independentsamples.Method: Thirteen selected measures were compared among affectedsibling pairs (ASPs) from Pittsburgh, USA and New Delhi, India(48 US pairs, 53 Indian pairs). For each ASP proband, anunrelated patient was selected randomly from a suitable pool ofcases ascertained in the same study (Sibpair proband—comparisoncase or S-C pairs). Correlations between these pairs werecompared.Results: The correlations varied by item and by site. Significantcorrelations for longitudinal course and pattern of severitywere noted among the ASPs from USA, but did not remainsignificant following corrections for multiple comparisons.Comparisons between the correlations for ASPs and the S-C pairs,used to estimate familial effects, yielded trends for the ASPcorrelations to be numerically larger than the S-C correlationsin both samples. Separate cross-site comparisons revealedseveral significant differences with regard to severaldemographic and clinical variables. The possible impact of thecross-site variations on the observed ASP correlations isdiscussed.Conclusions: Though familial factors did not appear to have asignificant impact on course/severity using this novel design,the suggestive trends need to be examined in largersamples.