A diagnostic classification version of Schizotypal Personality Questionnaire using diagnostic classification models

To obtain more precise and rich information from the measurements for schizotypal personality disorder (SPD), a cutting-edge psychometric theory called diagnostic classification models (DCMs) was first employed in the present study to develop a diagnostic classification version of the Schizotypal Personality Questionnaire (DC-SPQ) based on the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders.

Under the framework of DCMs, 980 college students were recruited to calibrate item parameters of the Schizotypal Personality Questionnaire. Items that fit the psychometric characteristic would be selected to compose the DC-SPQ, prior to an analysis of its indexes.

Results showed that the DC-SPQ had high reliability and validity in both the classical test theory and DCMs, in addition to showing a sensitivity of 0.921 and a specificity of 0.841 with area under receiver operating characteristic curve = 0.936. Meanwhile, the four-factor model proposed adequately fits with the data. More importantly, the DC-SPQ provides not only the general-level information similar to traditional questionnaires but also the symptom-level information with the posterior probability, which provides an insight into delivering the individual-specific intervention that is tailor made to schizotypal personality disorder.

This study demonstrates that the DC-SPQ is very valuable for psychometric detection in that it can clarify the symptom being measured and provide more reasonable estimates.