• With the exception of one finding in one experiment, adoption studies have demonstrated that genetic and not rearing factors play an etiological role in the schizophrenias. In that one study, clinical evaluations showed the biological parents of schizophrenics as more disturbed than the adopting parents of schizophrenics, who were, in turn, slightly more disturbed than the adopting parents of normal persons. Both the biological and the adopting parents of schizophrenics showed an equivalent degree of Rorschach pathology, suggesting the possible role of a learned communication disorder in the schizophrenic disorders. A replicative study was performed, employing the same design but utilizing a systematic sample. Structured interviews and tests were administered to the biological parents of nongenetic retardates. Structured clinical evaluation showed the biological parents of schizophrenics to be more disturbed than the other two groups, between whom there was no difference in psychopathology. With analysis of the Rorschach tests, the biological parents of schizophrenics showed significantly more Rorschach pathology than found in the other two groups, whose degree of disorder was the same. This study again confirms the role of genetic factors and fails to show an environmental component in the etiology of the schizophrenias.
Wender PH, Rosenthal D, Rainer JD, Greenhill L, Sarlin MB. Schizophrenics' Adopting ParentsPsychiatric Status. Arch Gen Psychiatry. 1977;34(7):777-784. doi:10.1001/archpsyc.1977.01770190039003