title: The Schizophrenia Proneness Instrument, Child and Youth version (SPI-CY): practicability and discriminative validity.
abstract: BACKGROUND
  Basic symptom (BS) criteria have been suggested to complement ultra-high risk (UHR) criteria in the early detection of psychosis in adults and in children and adolescents. To account for potential developmental particularities and a different clustering of BS in children and adolescents, the Schizophrenia Proneness Instrument, Child and Youth version (SPI-CY) was developed.
  
  
  OBJECTIVE
  The SPI-CY was evaluated for its practicability and discriminative validity.
  
  
  METHODS
  The SPI-CY was administered to 3 groups of children and adolescents (mean age 16; range = 8-18; 61% male): 23 at-risk patients meeting UHR and/or BS criteria (AtRisk), 22 clinical controls (CC), and 19 children and adolescents from the general population (GPS) matched to AtRisk in age, gender, and education. We expected AtRisk to score highest on the SPI-CY, and GPS lowest.
  
  
  RESULTS
  The groups differed significantly on all 4 SPI-CY subscales. Pairwise post-hoc comparisons confirmed our expectations for all subscales and, at least on a descriptive level, most items. Pairwise subscale differences indicated at least moderate group effects (r ≥ 0.37) which were largest for Adynamia (0.52 ≤ r ≥ 0.70). Adynamia also performed excellent to outstanding in ROC analyses (0.813 ≤ AUC ≥ 0.981).
  
  
  CONCLUSIONS
  The SPI-CY could be a helpful tool for detecting and assessing BS in the psychosis spectrum in children and adolescents, by whom it was well received. Furthermore, its subscales possess good discriminative validity. However, these results require validation in a larger sample, and the psychosis-predictive ability of the subscales in different age groups, especially the role of Adynamia, will have to be explored in longitudinal studies.
authors.affiliation: University Hospital of Child and Adolescent Psychiatry, University of Cologne, Robert-Koch-Str 10, Gebäude 53, 50931 Cologne, Germany. lucienarmandfux@gmx.de
authors.forename: Lucien
authors.initials: L
authors.lastname: Fux
authors.forename: Petra
authors.initials: P
authors.lastname: Walger
authors.forename: Benno G
authors.initials: BG
authors.lastname: Schimmelmann
authors.forename: Frauke
authors.initials: F
authors.lastname: Schultze-Lutter
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology