Sex differences in self-reported schizotypal traits in relatives of schizophrenic probands

We used the Schizotypal Personality Questionnaire to evaluate schizotypal traits in 44 normal volunteers and 40 non-psychotic, biological relatives of schizophrenic probands. Relatives endorsed more cognitive-perceptual traits than did controls; a group-by-sex interaction indicated that male relatives accounted for this difference. Although not statistically significant, a similar pattern was observed for interpersonal traits. Thus, elevated rates of some schizotypal traits appear to be more prominent in male than in female relatives of schizophrenic probands, at least when assessed by self-report. Subscale analysis indicated that differences were accounted for primarily by suspiciousness and ideas of reference, suggesting that paranoid-like phenomena from both the cognitive-perceptual and interpersonal factors may constitute an important dimension of schizotypy in relatives. Unlike previous studies, we did not find any differences in constricted affect or disorganization signs. Interviews and other non-self-report techniques are probably best suited for an assessment of these features, although the question remains as to whether the combination of both approaches might provide some incremental discriminatory power.