Representing Schizotypal Thinking With Dimensional Traits: A Case for the Five Factor Schizotypal Inventory

Building on support for the five-factor model (FFM) of personality disorder, the Five Factor Schizotypal Inventory (FFSI) was developed to assess maladaptive traits relevant to schizotypal personality disorder. While the development of the FFSI supports a continuity between schizotypal thinking and perception (STAP) and the FFM domain of Openness to Experience, other studies show inconsistent findings concerning the strength of this relationship. The current study evaluates these relationships by investigating specific components of a short-form of the FFSI (e.g., the FFSI-SF) and 2 other measures of maladaptive traits with the lower order components within commonly employed measures of Openness to Experience. Nomological network similarities were evaluated for the relation of these scales with a series of conceptually relevant variables including intelligence, creativity, and positive schizotypy in a sample of 403 undergraduates, including 102 that were prescreened for elevated symptoms of schizotypal personality disorder (PD). These analyses revealed strong relations across the 3 measures of traits relevant to STAP, supporting the validity of the FFSI-SF. Most notably, 2 specific scales- Multidimensional Personality Questionnaire (MPQ) Absorption and Openness to Fantasy appeared to best capture the core variance across these measures. Furthermore, a nuanced pattern of relations suggested that specific components of STAP (e.g., oddity and fantasy proneness) matched closely with components of Openness to Experience. The results provide additional support for view that schizotypal thinking can be well-captured by personality dimensions that run continuously across normal and pathological levels. Public Significance Statement This study advances the hypothesis that aspects of schizotypy, including odd beliefs and behaviors, are indeed linked along the same dimension as Openness to Experience from general personality. This supports the idea that personality disorders can be understood as maladaptive expressions of normal personality traits and provides more evidence supporting future changes to the definition of personality disorders.