THE STRUCTURE OF SELF-REPORT SCHIZOTYPY IN TWINS

Many self-report scales have been proposed to measure in nonclinical populations the predisposition to schizophrenia, or "schizotypy." We here examine responses to 10 such scales from 409 twins from the population-based Virginia Register. Factor analysis indicates that schizotypy, as assessed by these scales, is not unidimensional. Rather, 3 distinct factors are found: positive trait schizotypy, nonconformity, and social schizotypy. These 3 factors are relatively distinct from the personality trait neuroticism and from self-report symptoms of anxiety and depression. However, social schizotypy is closely related to the personality dimension of extraversion. Twin model fitting indicates that genetic factors are important for all individual scales except perceptual aberration and for all 3 factors. Heritability estimates were often substantial (e.g. > 0.45). Conclusive evidence is still lacking to demonstrate which, if any, of the genetically influenced "schizotypy" factors reflect the inherited liability to schizophrenia.