title: The Prodromal Questionnaire: a case for IRT-based adaptive testing of psychotic experiences?
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 © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Interdisciplinary Center Psychopathology and Emotion Regulation (ICPE), University Medical Center Groningen, The Netherlands.|Department of Education and Research, GGZ Friesland, Leeuwarden, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: van Bebber
authors.affiliation: Interdisciplinary Center Psychopathology and Emotion Regulation (ICPE), University Medical Center Groningen, The Netherlands.|Department of Education and Research, GGZ Friesland, Leeuwarden, The Netherlands.|University Medical Center Groningen, Rob Giel Research Center (RGOc), University of Groningen, The Netherlands.
authors.forename: Johanna T W
authors.initials: JTW
authors.lastname: Wigman
authors.affiliation: Department of Psychometrics and Statistics, University of Groningen, Groningen, The Netherlands.
authors.forename: Rob R
authors.initials: RR
authors.lastname: Meijer
authors.affiliation: Department of Psychiatry, Parnassia Psychiatric Institute, The Hague, The Netherlands.
authors.forename: Helga K
authors.initials: HK
authors.lastname: Ising
authors.affiliation: Department of Psychiatry, Parnassia Psychiatric Institute, The Hague, The Netherlands.
authors.forename: David
authors.initials: D
authors.lastname: van den Berg
authors.affiliation: Department of Psychiatry, Parnassia Psychiatric Institute, The Hague, The Netherlands.
authors.forename: Judith
authors.initials: J
authors.lastname: Rietdijk
authors.affiliation: Department of Psychiatry, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Sara
authors.initials: S
authors.lastname: Dragt
authors.affiliation: Department of Child and Adolescent Psychiatry, University Medical Center Utrecht.
authors.forename: Rianne
authors.initials: R
authors.lastname: Klaassen
authors.affiliation: Department of Psychiatry, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Dorien
authors.initials: D
authors.lastname: Nieman
authors.affiliation: Interdisciplinary Center Psychopathology and Emotion Regulation (ICPE), University Medical Center Groningen, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: de Jonge
authors.affiliation: Interdisciplinary Center Psychopathology and Emotion Regulation (ICPE), University Medical Center Groningen, The Netherlands.
authors.forename: Sjoerd
authors.initials: S
authors.lastname: Sytema
authors.affiliation: Interdisciplinary Center Psychopathology and Emotion Regulation (ICPE), University Medical Center Groningen, The Netherlands.
authors.forename: Marieke
authors.initials: M
authors.lastname: Wichers
authors.affiliation: Department of Psychiatry, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Don
authors.initials: D
authors.lastname: Linszen
authors.affiliation: Department of Psychiatry, Parnassia Psychiatric Institute, The Hague, The Netherlands.|VU University and EMGO+ Institute for Health and Care Research, Amsterdam, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: van der Gaag
authors.affiliation: Department of Education and Research, GGZ Friesland, Leeuwarden, The Netherlands.
authors.forename: Lex
authors.initials: L
authors.lastname: Wunderink
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D000066505:Help-Seeking Behavior; D006801:Humans; D008297:Male; D015233:Models, Statistical; D009426:Netherlands; D011237:Predictive Value of Tests; D062706:Prodromal Symptoms; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000523:psychology*; D015203:Reproducibility of Results; D057566:Self Report; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires
keywords: computerized adaptive tests; item response theory; psychosis; real data simulations