A family study of psychotic symptomatology in schizophrenia, schizoaffective disorder, unipolar depression, and bipolar disorder.

An evaluation was made of schizophrenics (140), schizoaffectives (40), unipolar depressives (59), and bipolars (30), and their relatives who had a chart diagnosis of psychosis or depressive neurosis. The purpose was to determine whether the psychosis (delusions and hallucinations) was transmitted independently of the illness itself. If this were true, there would be an excess of pairs of probands and relatives both positive for psychosis and pairs of relatives and probands both negative for psychosis when compared to relatives and probands who were not concordant for the variable. This was found to be true in schizophrenia and schizoaffective disorder and is probably the result of the simple transmission of an illness which includes the presence of psychotic symptoms in the definition. Thus, this would be a manifestation of the genetic propensity in schizophrenia. For the affective disorders there was no evidence that psychotic probands were more likely than the nonpsychotic to have psychotic relatives. So far the reason why some patients have psychosis and others not in the affective disorders remains unexplained.