Schizotypy: phenotypic marker as risk factor.

OBJECTIVE

To evaluate measures of schizotypy as familial risk factors for schizophrenia with the aim of making recommendations for assessing schizotypy as part of screening procedures for identifying people at risk of schizophrenia.

METHOD

Published studies using self-report and interview-based measures of schizotypy to assess relatives of patients with schizophrenia are reviewed. A parent study is reported evaluating the diagnostic accuracy of parental schizotypy as assessed by three questionnaire-based measures: the Chapman Perceptual Aberration and Physical Anhedonia Scales, and the Eysenck Psychoticism Scale. Group scores for these self-report ratings of 23 parent-pairs of patients with schizophrenia, 20 parent-pairs of patients with chronic nonpsychotic psychiatric disorder, and 19 parent-pairs of healthy comparison subjects are compared.

RESULTS

Consistent with published evidence that self-report measures of psychosis-proneness and schizotypy do not consistently reflect familial risk factors that are specific for schizophrenia, scores on questionnaire measures of schizotypy did not distinguish the parents of patients with schizophrenia from the parents in the other two groups.

CONCLUSIONS

Interview-based assessments of schizotypy better assess familial risk factors than self-report measures of schizotypy. Questionnaire measures of schizotypy should be supplemented by interview-based assessments when screening for individuals at risk of schizophrenia.