Abstract
Given the common use of self-report questionnaires to assess schizotypy in personality pathology and schizophrenia research, it is important to determine the concordance between self-report and clinician ratings. 250 individuals with schizotypal personality disorder (SPD) and 116 community controls (CTR) were assessed on schizotypal traits using a clinical interview, the Structured Interview for DSM-IV Personality disorders (SIDP), and a self-report questionnaire, the Schizotypal Personality Questionnaire (SPQ). Ordinal logistic regressions examined concordance between self-reported and clinician-rated scores in CTR and SPD separately. Analyses of variance examined how the SPQ performed on differentiating between CTR with low schizotypy, CTR with high schizotypy, and SPD. For both CTR and SPD, higher SPQ subscale scores were significantly associated with higher clinician ratings on the respective SIDP items for the Ideas of Reference, Magical Thinking, Unusual Perceptual Experience, Suspiciousness, and Social Anxiety items, but not the Odd Speech or Limited Affect items. Higher SPQ subscale scores for Odd Behavior and Lack of Close Friends were significantly associated with the clinician-rated SIDP item scores in CTR but not SPD. CTR with low schizotypy scored lower on all SPQ subscales than CTR with high schizotypy, who did not differ from SPD. Self-report ratings are concordant with clinician ratings for positive schizotypal traits, whereas certain disorganization and interpersonal traits are not, particularly for individuals with SPD. The SPQ can differentiate between high and low schizotypy controls, but not between high schizotypy controls and individuals with SPD. Assessment of schizotypal traits should include both self-report questionnaires and clinician ratings.