title: The Italian version of the 92-item Prodromal Questionnaire: Concurrent validity with the SIPS and factor analysis in a sample of 258 outpatients aged 11-36years.
abstract: Current early screeners for psychosis-risk states have still to prove ability in identifying at-risk individuals. Among screeners, the 92-item Prodromal Questionnaire (PQ-92) is often used. We aimed to assess the validity of its Italian translation in a large Italian adolescent and young adult help-seeking sample.
  
  
  
  We included all individuals aged 12-36years seeking help at psychiatric mental health services in a large semirural Roman area (534,600 population) who accepted to participate. Participants completed the Italian version of the PQ-92 and were subsequently assessed with the Structured Interview of Prodromal/Psychosis-Risk Syndromes (SIPS). We examined diagnostic accuracy (sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios) and content, concurrent, and convergent validity between PQ-92 and SIPS using Cronbach's alpha, Cohen's kappa, and Spearman's rho, respectively. We tested the validity of adopted cut-offs through Receiver Operating Characteristic (ROC) curves plotted against SIPS diagnoses and the instrument's factor-structure through Principal Component Analysis.
  
  
  
  PQ-92 showed high internal consistency, acceptable diagnostic accuracy and concurrent validity, and excellent convergent validity. ROC analyses pointed to scores of 18 on the Positive subscale and 36 on the total PQ-92 as best cut-offs. The Scree-test identified a four-factor solution as fitting best.
  
  
  
  Psychometric properties of Italian PQ-92 were satisfactory. Optimal cut-offs were confirmed at ≥18 on the positive subscale, but at ≥36 on the total scale was able to identify more SIPS-positive cases.
authors.affiliation: NESMOS Department, Sapienza University, School of Medicine and Psychology, Sant'Andrea Hospital, Rome, Italy. Electronic address: giorgio.kotzalidis@uniroma1.it.
authors.forename: Georgios D
authors.initials: GD
authors.lastname: Kotzalidis
authors.affiliation: NESMOS Department, Sapienza University, School of Medicine and Psychology, Sant'Andrea Hospital, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Solfanelli
authors.affiliation: NESMOS Department, Sapienza University, School of Medicine and Psychology, Sant'Andrea Hospital, Rome, Italy.
authors.forename: Daria
authors.initials: D
authors.lastname: Piacentino
authors.affiliation: ASL RM3, Rome, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Savoja
authors.affiliation: Department of Psychiatric Sciences, Sapienza School of Medicine and Dentistry, Policlinico Umberto I, Rome, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Fiori Nastro
authors.affiliation: NESMOS Department, Sapienza University, School of Medicine and Psychology, Sant'Andrea Hospital, Rome, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Curto
authors.affiliation: NESMOS Department, Sapienza University, School of Medicine and Psychology, Sant'Andrea Hospital, Rome, Italy.
authors.forename: Juliana Fortes
authors.initials: JF
authors.lastname: Lindau
authors.affiliation: Department of Psychiatric Sciences, Sapienza School of Medicine and Dentistry, Policlinico Umberto I, Rome, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Masillo
authors.affiliation: Department of Psychiatric Sciences, Sapienza School of Medicine and Dentistry, Policlinico Umberto I, Rome, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Brandizzi
authors.affiliation: PIPSM (Prevention and Early Intervention for Mental Health) Service, ASL RM1, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Fagioli
authors.affiliation: Norwegian Centre for Mental Disorders Research (NORMENT), University of Oslo, Norway.
authors.forename: Andrea
authors.initials: A
authors.lastname: Raballo
authors.affiliation: Department of Psychiatric Sciences, Sapienza School of Medicine and Dentistry, Policlinico Umberto I, Rome, Italy.
authors.forename: Eva
authors.initials: E
authors.lastname: Gebhardt
authors.affiliation: Center of Liaison Psychiatry and Psychosomatics, University Hospital of Cagliari, Cagliari, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Preti
authors.affiliation: ASL RM6, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: D'Alema
authors.affiliation: ASL RM6, Rome, Italy.
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Fucci
authors.affiliation: ASL RM6, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Miletto
authors.affiliation: ASL RM6, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Andropoli
authors.affiliation: ASL RM6, Rome, Italy.
authors.forename: Donato
authors.initials: D
authors.lastname: Leccisi
authors.affiliation: NESMOS Department, Sapienza University, School of Medicine and Psychology, Sant'Andrea Hospital, Rome, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Girardi
authors.affiliation: Department of Psychiatry, University of California, 401 Parnassus Avenue, Box PAR-0984, San Francisco, CA 94143, United States.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Loewy
authors.affiliation: University Hospital of Child and Adolescent Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland.
authors.forename: Frauke
authors.initials: F
authors.lastname: Schultze-Lutter
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D010045:Outpatients; D062706:Prodromal Symptoms; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000523:psychology*; D012372:ROC Curve; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000175:diagnosis; D012565:Schizophrenic Psychology; D011795:Surveys and Questionnaires; D014175:Translating; D055815:Young Adult
keywords: At-Risk Mental State; Early identification; Prodromal Questionnaire; Prodrome; Schizophrenia; Screening tests