Replicated evidence that endophenotypic expression of schizophrenia polygenic risk is greater in healthy siblings of patients compared to controls, suggesting gene–environment interaction. The EUGEI study

Background First-degree relatives of patients with psychotic disorder have higher levels of polygenic risk (PRS) for schizophrenia and higher levels of intermediate phenotypes. Methods We conducted, using two different samples for discovery ( n = 336 controls and 649 siblings of patients with psychotic disorder) and replication ( n = 1208 controls and 1106 siblings), an analysis of association between PRS on the one hand and psychopathological...