The Prodromal Questionnaire: A case for IRT-based adaptive testing of psychotic experiences?

Jan van Bebber*, Johanna T. W. Wigman, Rob R. Meijer, Helga K. Ising, David van den Berg, Judith Rietdijk, Sara Dragt, Rianne Klaassen, Dorien Nieman, Peter de Jonge, Sjoerd Sytema, Marieke Wichers, Don Linszen, Mark van der Gaag, Lex Wunderink

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

Computerized adaptive tests (CATs) for positive and negative psychotic experiences were developed and tested in N=5705 help-seeking, non-psychotic young individuals. Instead of presenting all items, CATs choose a varying number of different items during test administration depending on respondents' previous answers, reducing the average number of items while still obtaining accurate person estimates. We assessed the appropriateness of two-parameter logistic models to positive and negative symptoms of the Prodromal Questionnaire (PQ), computed measurement precision of all items and resulting adaptive tests along psychotic dimensions by Real Data Simulations (RDS), and computed indices for criterion and predictive validities of the CATs. For all items, mean absolute differences between observed and expected response probabilities were smaller than 0.02. CAT-POS predicted transition to psychosis and duration of hospitalization in individuals at-risk for psychosis, and CAT-NEG was suggestively related to later functioning. Regarding psychosis risk classifications of help-seeking individuals, CAT-POS performed less than the PQ-16. Adaptive testing based on self-reported positive and negative symptoms in individuals at-risk for psychosis is a feasible method to select patients for further risk classification. These promising findings need to be replicated prospectively in a non-selective sample that also includes non-at-risk individuals. Copyright (c) 2016 John Wiley & Sons, Ltd.

Original languageEnglish
Article numbere1518
Number of pages11
JournalInternational Journal of Methods in Psychiatric Research
Volume26
Issue number2
DOIs
Publication statusPublished - Jun-2017

Keywords

  • psychosis
  • item response theory
  • computerized adaptive tests
  • real data simulations
  • ULTRA-HIGH-RISK
  • ITEM RESPONSE THEORY
  • FOLLOW-UP
  • 1ST-EPISODE PSYCHOSIS
  • UNTREATED PSYCHOSIS
  • INITIAL PRODROME
  • SCHIZOPHRENIA
  • PREDICTION
  • DURATION
  • MODEL

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