A developmentally-stable pattern of premorbid schizoid-schizotypal features predicts psychotic transition from the clinical high-risk for psychosis state

Background: Despite the extensive research performed on prediction of psychosis from a Clinical High Risk for Psychosis state (CHR-P), the positive predictive value of the CHR-P designation remains unsatisfactory and further models including additional clinical and biological variables are required. Existing studies indicate that schizotypy assessed at baseline in "at-risk" individuals may be considered a predictor of transition from CHR-P to psychosis. This approach, however, is burdened with bias resulting from a possible overlap between current psychopathology and schizotypal features. No studies so far have assessed schizotypy in CHR-P from a developmental perspective. Aim: The aim of the study was to identify associations between a long-standing, parent-reported premorbid level of schizoid-schizotypal traits and the probability of psychotic transition in individuals with CHR-P. Methods: The mothers of 107 individuals diagnosed as presenting CHR-P with the use of Comprehensive Assessment of At Risk Mental States12/2006 were interviewed with the Scale for the Assessment of Premorbid Schizoid-Schizotypal Traits (PSST). Results: A high level of enduring schizotypy was found to be significantly associated with psychotic transition from CHR-P (HR: 1.78, 95% CI: 1.40-2.27, p < 0.0001), as indicated by the proportional hazards model, adjusted for age, sex and clinical covariates potentially related to the outcome. PSST items comprising negative schizotypy appeared to be the strongest predictors of transition. Conclusions: The assessment of parent-reported, present early in the development premorbid schizoid=schizotypal traits, which can be easily performed in clinical settings, may be of value in estimating the probability of transition from an "at risk" state to psychotic disorder. (C) 2019 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).