The inheritance of a complex illness such as schizophrenia likely involves
the segregation of genetic factors, in combination with non-genetic or envi
ronmental abnormalities. This paper reviews several family studies of biolo
gical and clinical aspects of schizophrenia, that have attempted to observe
such segregation in relationship to family history of schizophrenia to ide
ntify which factors appear to be related to the transmission of genetic ris
k. (C) 1999 Elsevier Science Ltd. All rights reserved.