The factor structure of schizotypal symptoms in a clinical population

There is some support for the hypothesis that the factor structure of schizophrenia symptoms is similar to the factor structure of schizotypal symptoms in nonschizophrenia populations. However, no studies to date have examined schizotypal symptoms in patients with personality disorders. In this study, confirmatory factor analyses were conducted to test the relative fit of several models of the factorial structure of schizotypal symptoms in patients diagnosed with personality disorders. The EQS: Structural Equations Program was used to analyze DSM-III symptoms of schizotypal personality disorder (SPD) based on structured clinical interviews with 213 patients meeting a diagnosis for at least one personality disorder. A subgroup of the total sample was also evaluated for DSM-III-R criteria (n = 143) to test competing models of the DSM-III-X symptoms of SPD. A three-factor model consisting of a cognitive-perceptual, interpersonal, and paranoid factor yielded the best fit to the data relative to the other models tested. These results suggest that the three-factor model of schizophrenia symptoms may not entirely correspond to the factors underlying milder schizotypal symptoms expressed in a clinical population. It is suggested that future research focus on both the similarities and the differences between SPD and schizophrenia.