Parents of the Schizophrenic Patient: A Reconsideration*

Geneticists have been able to offer presumptive evidence that a hereditary factor exists in schizophrenia. When different studies, carried out in different countries and with different methodologies, disclose that if schizophrenia occurs in a monozygotic twin, in at least 35% of cases it will develop sooner or later in the other member of the pair, even if the twins were reared apart, the evidence is persuasive. In fact, the incidence of schizophrenia in the general population is calculated to be only 0.85%.

This evidence, however, is not sufficient to explain the whole etiology of schizophrenia. First of all, it is inferred from statistics, but not proved. No Mendelian law acting in families of schizophrenics has been found. No distribution of schizophrenia resembling that of such hereditary diseases as Huntington's chorea, hemophilia, or muscular dystrophy has been observed. Moreover, if monozygotic twins are genetically equivalent, the concordance in relation to schizophrenia should be 100% in these cases; but it is not. These considerations and others suggest that although the genetic factor is important, it provides only a potentiality, but other factors are necessary to change a potentiality into a clinical entity. The speaker is one of the numerous authors who have searched for the missing etiological links in the environment of the patient. Like many other authors, he has found not even a single case, among the patients studied psychodynamically, who did not come from a disturbed milieu and did not present a very revealing psychodynamic history. It is thus plausible to assume that the