Cognitive profiles of schizotypal dimensions in a community cohort: Common properties of differential manifestations.

Introduction: Studies assessing the effects of schizotypal dimensions (i.e., positive, negative, and disorganized) on cognitive functions have yielded mixed findings. In the present study, we administered an extensive battery of cognitive tasks to a community sample and defined the schizotypal dimensions according to a more analytical four-factor model, whereby positive schizotypy is further divided into cognitive-perceptual and paranoid.

Method: Two hundred healthy community participants were assessed for schizotypy with the Schizotypal Personality Questionnaire; assessment of cognitive functions included set shifting, working memory, processing speed, verbal fluency, attention switching, planning/problem solving, strategy formation, and abstract reasoning. Associations between cognitive tasks and schizotypy were examined with hierarchical multiple linear regressions. We also divided our subjects into groups based on whether or not their scores in the negative, positive, and cognitive-perceptual factors fell in the upper 10% of the scores of a large community normative sample in Greece and examined between-group differences.

Results: Applying both dimensional and categorical approaches, we showed that (a) attention-switching impairment is a "core" deficit of both negative and paranoid schizotypy, (b) impaired working memory and set shifting are associated mainly with negative and to a lesser extent paranoid schizotypy, (c) paranoid schizotypy is associated with reduced performance in tasks requiring intact frontotemporal connectivity, and (d) cognitive-perceptual and disorganized schizotypy are not associated with any cognitive functions.

Conclusions: Our findings further support the more analytical four-factor categorization of schizotypy and suggest that the discrepancies in the findings so far might be due to a more "generalized" definition of the schizotypal dimensions. They also add further in the early formulation of the profile of the high-schizotypal individuals seeking psychiatric help so that their overall management is directed towards a more targeted approach.