This paper discusses the role of family variables in the development of schizophrenia. Other theories regarding the etiology of schizophrenia are summarized to show the complexity of the problem. Both biological and psychosocial factors are discussed. The review of current developments is organized around three family characteristics that have emerged as distinguishing families with schizophrenic members from families without schizophrenic members: (1) expressed emotion; (2) affective style; and (3) communication deviance. The construct validity of these characteristics is discussed. The problem of whether these family characteristics are results of the illness or contributing factors in the development of schizophrenia is analyzed according to recent longitudinal and treatment studies. In spite of the improvement of prediction of schizophrenic outcome by combining the measures or by dividing the expressed emotion measure into subtypes, current family studies are still unable to conclusively answer the etiological question regarding schizophrenia. It is recommended that a multivariate conceptualization of the etiology of schizophrenia be used, which incorporates biological, psychosocial, and family variables. (Author/NB)