Factor versus cluster models of schizotypal traits. II: relation to neuropsychological impairment

Abstract 

Heterogeneity in cognitive performance in schizophrenia and schizotypy may be accounted for, by differences in predominant symptom presentation. However, studies have not demonstrated consistent relations between specific cognitive impairments and specific trait dimensions in either population. Studies of group differences, particularly those using groups defined by cluster analyses are rare, but suggest that the negative trait dimension is more associated with executive function deficits, positive trait dimension with memory and attentional difficulties, and the disorganized trait dimension with attention problems. The present study examined the relation of schizotypal trait dimensions and executive function deficits in schizotypal individuals using two methods. Correlations between schizotypal factor scores and cognitive measures demonstrated that high negative symptoms were associated with poor performance on the WCST, while high scores on other trait dimensions were related to a better WCST performance. High scores in all trait dimensions were related to the naı̈ve rater's observations of unusual social behavior. A cluster analysis revealed three groups of schizotypals (predominantly negative presentation, predominantly positive symptom presentation, and high on all dimensions). The cluster with predominantly negative symptoms performed worse, than all other schizotypal groups and unselected controls, on the WCST and a higher percentage of them were rated as clinically impaired on the neuropsychological battery. However, schizotypals who were high on all trait dimensions were rated as having the most unusual social behavior by the naı̈ve raters. Overall, results support the hypothesis of a relation between executive function deficits and negative symptoms in schizotypal individuals.

Keywords: Schizotypy, Neuropsychology, Symptom heterogeneity