Date of Degree
PhD (Doctor of Philosophy)
Lee Anna Clark
Dimensional models of schizotypy and associated traits have taken on current relevance in the DSM-5 (http://www.dsm5.org) proposal for personality disorder (PD), which includes a personality trait initially conceptualized as a five-facet schizotypy domain and then simplified into a three-facet psychoticism domain that has yet to be evaluated extensively. In this study, I (1) reviewed the literature to develop hypotheses about the content and boundaries of the schizotypy domain, and (2) measured this content in a mixed sample of students and patents with 657 usable protocols at Time 1 (193 Notre Dame students, 301 University of Iowa students; 163 outpatients) and 263 usable protocols (74 Notre Dame students, 76 University of Iowa students, 113 outpatients) at Time 2, at least 1.5 weeks later. I then (3) evaluated confirmatory models including DSM-5 schizotypy and psychoticism facet models and other empirically grounded models and (4) used the best confirmatory model to provide item pools for classically constructing scales of schizotypy facets. This four-factor structure provided content pools used to create four corresponding scales: Unusual Perceptions, Unusual Beliefs, Dissociation Proneness, and Cognitive and Communicative Peculiarity. Additionally, (5) I used item response theory (IRT)-based analyses to evaluate items in these facet scales, both in terms of the level of schizotypy they best measure and the strength of their relations to the schizotypy construct. I also (6) examined the short-term test-retest reliability of the schizotypy scales, as well as that of the established measures used in this study; new and existing measures were comparably stable. Finally, (7) I evaluated schizotypy's convergent and discriminant validity in relation to three other types of traits: (a) those correlated with the domain (e.g., Obsessive Compulsive Disorder [OCD] and non-delusional mistrust), (b) other higher level traits (i.e., measures of the 3 factor and 5-factor models of higher order personality/temperament), and (c) familially related traits (e.g., social anxiety). Overall, the schizotypy facet measures appeared to assess moderate amounts of variance that were unexplained by the established measures of personality, temperament, and psychopathology that were included in this study. The implications of adding a schizotypy trait to the overall personality trait taxonomy are discussed.
Copyright 2012 Deborah Michele Stringer
Stringer, Deborah Michele. "Schizotypy's shape: structure, items, and dependability." dissertation, University of Iowa, 2012.