Theories that link the development of schizophrenia to patterns of family interaction tend to assume that there are systematic differences in how parents interact with their patient child and with their nonpatient children. In this study, this assumption is tested with data derived from a small group experiment that included normal control families as well as the families of patients. A number of variables were examined including interpersonal control strategies, expressiveness, and responsiveness. Several alternative indices of parental interaction were constructed and examined including each parent's behavior, their combined behavior as a parental pair, and the relative amount of behavior directed towards the child. In no instance, for any variable or for any measure of parental interaction, was there a consistent and predictable change from a situation where the patient was present to one where the sibling was present.
Waxler NE, Mishler EG. Parental Interaction With Schizophrenic Children and Well SiblingsAn Experimental Test of Some Etiological Theories. Arch Gen Psychiatry. 1971;25(3):223-231. doi:10.1001/archpsyc.1971.01750150031005