Georgios D Kotzalidis1, Andrea Solfanelli2, Daria Piacentino2, Valeria Savoja3, Paolo Fiori Nastro4, Martina Curto2, Juliana Fortes Lindau2, Alice Masillo4, Martina Brandizzi4, Francesca Fagioli5, Andrea Raballo6, Eva Gebhardt4, Antonio Preti7, Marco D'Alema8, Maria Rosa Fucci8, Roberto Miletto8, Daniela Andropoli8, Donato Leccisi8, Paolo Girardi2, Rachel L Loewy9, Frauke Schultze-Lutter10. 1. NESMOS Department, Sapienza University, School of Medicine and Psychology, Sant'Andrea Hospital, Rome, Italy. Electronic address: giorgio.kotzalidis@uniroma1.it. 2. NESMOS Department, Sapienza University, School of Medicine and Psychology, Sant'Andrea Hospital, Rome, Italy. 3. ASL RM3, Rome, Italy. 4. Department of Psychiatric Sciences, Sapienza School of Medicine and Dentistry, Policlinico Umberto I, Rome, Italy. 5. PIPSM (Prevention and Early Intervention for Mental Health) Service, ASL RM1, Rome, Italy. 6. Norwegian Centre for Mental Disorders Research (NORMENT), University of Oslo, Norway. 7. Center of Liaison Psychiatry and Psychosomatics, University Hospital of Cagliari, Cagliari, Italy. 8. ASL RM6, Rome, Italy. 9. Department of Psychiatry, University of California, 401 Parnassus Avenue, Box PAR-0984, San Francisco, CA 94143, United States. 10. University Hospital of Child and Adolescent Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland.
Abstract
BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.