Schizotypal personality traits in nonpsychotic relatives are associated with positive symptoms in psychotic probands.

There remains disagreement over whether increased risk of schizotypal personality disorder (SPD) is confined to the relatives of patients with a diagnosis of schizophrenia or whether it is a more general characteristic of the relatives of all psychotic patients. To examine the relationship between schizotypal dimensions in relatives and psychopathological syndromes in patients with functional psychoses, factor analysis was carried out on (1) ratings from Present State Examination (PSE) interviews with 172 consecutively admitted patients with psychosis (52% of them with schizophrenia), and (2) ratings on items from three schizotypal scales concerning 263 of their nonpsychotic first degree relatives. The factors derived from the patients' PSE interviews were correlated with the schizotypal factors and the nine DSM-IV criteria for SPD concerning the relatives and subjected to a canonical correlation analysis. In this study, no differences were observed concerning the distribution of schizotypal factors or DSM-IV schizotypal features in the relatives of patients with different psychotic diagnoses. However, a syndrome characterized by delusions, hallucinations, and thought interference (positive symptoms) in patients was correlated with high scores on the three schizotypy scales and with positive and negative schizotypal features in relatives.