Detection of familial schizophrenia using a psychometric measure of schizotypy.

This study examined the lifetime expectancy (morbid risk) of schizophrenia, unipolar depression, and bipolar disorder in the first-degree relatives of 101 nonpsychotic psychiatric patients (probands) who were classified as schizotypy-positive or schizotypy-negative using a psychometric measure of schizotypy, the Perceptual Aberration Scale. The relatives of schizotypy-positive probands were significantly more likely to have been treated for schizophrenia than the relatives of schizotypy-negative probands. Morbid risk for unipolar depression or bipolar disorder among first-degree relatives did not differ between the proband groups. The results support Meehl's theory of the pathogenesis of schizophrenia and enhance the construct validity of the Perceptual Aberration Scale. The heuristic potential of a psychometric high-risk strategy in schizophrenia research is discussed and the need for replication of the present study is emphasized.