Protocol of the Psychometric High-Risk Strategy Project for Examining Risk and Resilience Trajectories across the Psychosis Continuum v1
Authors: Racioppi Anna , Sheinbaum Tamara , M. Gross Georgina , Ballespí Sergi , R. Kwapil Thomas , Barrantes-Vidal Neus 
Published: October 2018

The present study forms part of an ongoing longitudinal project examining risks and resilience for schizophrenia-spectrum disorders in a non-clinical ascertained sample of college students. The main objective of the study was examine the validity of psychometrically assessed positive and negative schizotypy at a three-year follow-up assessment (Time 3; T3) of the sample initially reported in the cross-sectional study of Barrantes-Vidal et al. (2013). Participants were recruited from the undergraduate population enrolled in Psychology courses at the Universitat Autònoma de Barcelona (UAB). A group of 589 unselected students completed a mass screening assessment of self-reported measures at Time 1 (T1). Participants were administered the Wisconsin Schizotypy Scales (WSS) intermixed with an infrequency scale, the positive symptoms subscale of the Community Assessment of Psychic Experiences (CAPE), and the suspiciousness subscale of the Schizotypal Personality Questionnaire (SPQ). Usable screening data were obtained from 547 students (mean age = 20.6; SD = 4.1; 86% female, 42 were excluded from the final study due to invalid protocols). Two interview and self-report measures assessments were conducted after T1. The Time 2 (T2) and Time 3 (T3) interviews were made by psychologists and advanced graduate students in clinical psychology. All interviewers were extensively trained and were unaware of participants' scores on the T1 and T2 measures. Of the 547 students who completed T1 assessment, a subset of 339 was invited to participate at T2 assessment with the aim of assessing 200 individuals. In order to ensure adequate inclusion of participants reporting high levels of schizotypy, the students group included 189 who had elevated scores (standard scores based upon sample norms of at least 1.0) on the positive or negative schizotypy factors derived from the WSS, or the SPQ-suspiciousness, or the CAPE, and 150 randomly selected participants who had standard scores below 1.0 on each of these measures.A total of 214 students (mean age = 21.4 years; SD = 2.4; 78% female) completed T2 assessment which took place an average of 1.7 years (SD= 0.2 years, range 1.4 to 2.2 years) after T1. This sample included 123 participants with at least one schizotypy screening score above 1.0 and 91 with standard scores below 1.0. The T3 assessment took place an average of 1.4 years (SD= 0.3 years, range 0.9 to 2.1 years) after T2, and of 3.1 years (SD= 0.3 years, range 2.6 to 3.6 years) after T1. At T3, due to financial limitation we targeted a subset of 134 students (93 with high schizotypy and 41 with standard scores below 1.0). Of these, 103 (77%) participants (mean age= 23.06; SD=2.6; 37.9% male) were interviewed at T3. The sample included 75 of 93 (82%) participants with elevated schizotypy scores and 28 of 43 (65%) with standard scores below 1.0. There were no significant differences on positive or negative schizotypy scores between the participants assessed at T3 and the non-followed participants. This study was conducted according to guidelines of the University Ethics Committee of the UAB and participants provided informed consent at each assessment.