The dimensional structure of short forms of the Wisconsin Schizotypy Scales Georgina M. Gross a , Paul J. Silvia a , Neus Barrantes-Vidal a,b,c,d , Thomas R. Kwapil a, ⁎ a University of North Carolina at Greensboro, NC, United States b Universitat Autònoma de Barcelona, Spain c Sant Pere Claver-Fundació Sanitària, Barcelona, Spain d Instituto de Salud Carlos III, CIBERSAM, Barcelona, Spain abstract article info Article history: Received 2 February 2015 Received in revised form 1 May 2015 Accepted 7 May 2015 Available online xxxx Keywords: Schizotypy Wisconsin Schizotypy Scales Schizophrenia Psychosis proneness The Wisconsin Schizotypy Scales (WSS) are widely used for assessing schizotypy. Confirmatory factor analysis (CFA) indicates that a two-factor structure, positive and negative schizotypy, underlies these scales. Recently developed 15-item short forms of the WSS demonstrated good reliability and validity. This study examined the factor structure underlying the short-form WSS. Consistent with the original scales, CFA on three large sam- ples (n = 6137, 2171, and 2292, respectively) indicated that a two-factor model with positive and negative dimensions provided better fit than a generic schizotypy model for the short-form WSS. The short-form dimen- sions correlated highly with the original scale dimensions and displayed good stability across 10 weeks. Prelim- inary construct validity was demonstrated through associations with interview and questionnaire measures of psychopathology, functioning, and personality comparable to those found with the original WSS. This is the first study examining the dimensional structure of the short WSS and the validity of these dimensions. The find- ings support the multidimensional nature of schizotypy and the appropriateness of dimensions derived from the short-form WSS. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Current research conceptualizes schizotypy as a multidimensional phenotype that encompasses clinical and subclinical manifestations of the schizophrenia spectrum (Lenzenweger, 2010; Kwapil and Barrantes-Vidal, 2014). Ample evidence supports significant overlap between schizotypy and schizophrenia across behavioral and neuro- biological domains, suggesting that the identification of schizotypic individuals should facilitate the detection of etiological risk and protec- tive factors for schizophrenia-spectrum disorders (for a review see Ettinger et al., 2014). It also allows for the examination of etiological factors relatively untainted by confounds accompanying full-blown schizophrenia, such as hospitalization, medication, and stigma. Since their development by the Chapmans and colleagues, the Wisconsin Schizotypy Scales (WSS, also known as the Chapman Scales of Psychosis Proneness)—including the Perceptual Aberration (Chapman et al., 1978), Magical Ideation (Eckblad and Chapman, 1983), Physical Anhedonia (Chapman et al., 1976), and Revised Social Anhedonia (Eckblad et al., 1982) Scales—have been widely employed in the study of schizotypy. Cross-sectional and longitudinal investigations provided evidence for the reliability and validity of the WSS (e.g., Gooding et al., 2005; Kwapil et al., 2008, 2013). Schizotypy, and by extension schizophrenia, are conceptualized as multidimensional constructs (Raine et al., 1994; Vollema and van den Bosch, 1995; Stefanis et al., 2004), with positive and negative symptom dimensions the most consistently replicated factors. Using confirmatory factor analysis (CFA) with 6137 young adults, Kwapil et al. (2008) found evidence for a two-factor structure with positive and negative factors underlying the original WSS. In addition, they reported that, as hypoth- esized, the schizotypy dimensions were differentially associated with symptoms and impairment. Positive schizotypy was associated with psychotic-like experiences, substance abuse, mood disorders, and men- tal health treatment; negative schizotypy was associated with negative and schizoid symptoms and decreased likelihood of intimate relation- ships. Both dimensions were related to schizotypal and paranoid symp- toms and poorer functioning. Kwapil et al. (2013) reported that both dimensions predicted schizophrenia-spectrum disorders using data from the 10-year follow-up study conducted by Chapman et al. (1994). Despite the demonstrated validity of the WSS, the combined length of the scales (166 items) can be problematic; therefore, Winterstein et al. (2011) created 15-item short forms for each of the four WSS. They chose items based upon content analysis and psychometric prop- erties using classical test theory, item response theory, and differential Schizophrenia Research xxx (2015) xxx–xxx ⁎ Corresponding author at: Department of Psychology, University of North Carolina at Greensboro, P.O. Box 26170, Greensboro, NC 27402-6170, United States. Tel.: +1 336 334 4758. E-mail address: t_kwapil@uncg.edu (T.R. Kwapil). SCHRES-06379; No of Pages 6 http://dx.doi.org/10.1016/j.schres.2015.05.016 0920-9964/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Schizophrenia Research journal homepage: www.elsevier.com/locate/schres Please cite this article as: Gross, G.M., et al., The dimensional structure of short forms of the Wisconsin Schizotypy Scales, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2015.05.016