Development and psychometric properties of the Multidimensional Schizotypy Scale: A new measure for assessing positive, negative, and disorganized schizotypy

Abstract

This article reports on the development of a new self-report questionnaire measure of schizotypy - the Multidimensional Schizotypy Scale (MSS). Schizotypy offers a useful and unifying construct for understanding schizophrenia-spectrum psychopathology. Questionnaire measures have been widely used to assess schizotypy and have greatly informed our understanding of the construct. However, available measures suffer from a number of limitations, including lack of a clear conceptual framework, outdated wording, unclear factor structure, and psychometric shortcomings. The MSS is based on current conceptual models and taps positive, negative, and disorganized dimensions of schizotypy. The derivation sample included 6265 participants sampled from four universities and Amazon Mechanical Turk. A separate sample of 1000 participants from these sources was used to examine the psychometric properties of the final subscales. Scale development employed classical test theory, item response theory, and differential item function methods. The positive schizotypy and negative schizotypy subscales contain 26 items each, and the disorganized schizotypy subscale contains 25 items. The psychometric properties were almost identical in the derivation and validation samples. All three subscales demonstrated good to excellent reliability, high item-scale correlations, and good item and test curve characteristics. The MSS appears to provide a promising measure for assessing schizotypy.

Differential emotional abnormalities among schizotypy clusters

“…Of these, 173 individuals were excluded because they did not complete the Wisconsin Schizotypy Scales. In addition, following previous research (e.g., Barrantes-Vidal et al, 2010;Chmielewski et al, 1995;Kwapil et al, 2018;Martin et al, 2011), 673 participants were excluded because they endorsed 3 or more items on the Chapman Infrequency Scale (Chapman and Chapman, 1983), which measures careless or invalid responses. The final derivation sample included in the analyses consisted of 2516 participants (mean age = 20.60, SD = 3.34; see Table 1 for demographic characteristics).…”

Exploratory Graph Analysis of the Multidimensional Schizotypy Scales

“…The two samples used in this study were the same large samples used to develop and cross-validate the MSS and MSS-B (Gross et al, 2018b;Kwapil et al, 2018b). In total, 8750 people were recruited from four universities and Amazon's Mechanical Turk (MTurk) over a two-year span.…”

“…All participants completed candidate items for the MSS, and these items were refined and trimmed to produce the final full-length and brief scales. Extensive demographic and methodological information for both samples used in this study, as well as detailed information about the development of the MSS and MSS-B can be found in Kwapil et al (2018b) and Gross et al (2018b). In short, participants with elevated scores on measures of inattentive and invalid responding or who did not complete half of the items were removed from the datasets.…”

“…Item selection was based upon the derivation sample, whereas the cross-validation sample was used to assess the psychometric properties of the final inventory (Kwapil et al, 2018b).…”

“…In the present study, we sought to evaluate the dimensional structure of the Multidimensional Schizotypy Scale (MSS; Kwapil et al, 2018b) and its brief version, Multidimensional Schizotypy Scale-Brief (MSS-B; Gross et al, 2018b), using EGA in two large samples. The MSS and MSS-B were developed to assess positive, negative, and disorganized schizotypy.…”