The multidimensional nature of schizotypal traits: a factor analytic study with normal subjects.

Fourteen published scales of psychotic traits or symptoms (measuring various delusional states, magical ideation, perceptual aberration, disposition towards hallucination, hypomanic personality, schizotypal personality, borderline personality and anhedonia) were combined with the Eysenck Personality Questionnaire to form a Combined Schizotypal Traits Questionnaire (CSTQ) which was administered to 180 normal subjects. Two factor analyses were carried out on the scale scores. The first analysis excluded symptom scores derived from the Delusions Symptoms States Inventory of Foulds and Bedford and yielded a three-factor solution which appeared to measure traits relating to (i) positive psychotic symptomatology; (ii) negative psychotic symptomatology; and (iii) aspects of schizotypy involving social anxiety and cognitive disorganization. The Foulds scales were included in the second analysis which yielded a four-factor solution. The first three factors were similar to those obtained from the first analysis; the fourth factor seemed to measure an asocial component of schizotypy. This last factor was mainly accounted for by the P scale from the EPQ. These results support previous findings suggesting that different schizotypy scales relate to different underlying aspects of schizophrenia. The findings also indicate that psychotic traits are distributed along at least three dimensions.