Quick identification of the risk of psychosis: the Italian version of the prodromal questionnaire-brief

Antonio Preti

First

Member of the Collaboration Group

;Andrea Raballo

Member of the Collaboration Group

;Georgios D. Kotzalidis

Conceptualization

;SCANU, ROSANNA

Data Curation

;Tamara Muratore

Data Curation

;GABBRIELLI, MERSIA

Data Curation

;Debora Tronci

Data Curation

;Carmelo Masala

Second

Member of the Collaboration Group

;Donatella Rita Petretto

Penultimate

Member of the Collaboration Group

;Mauro Giovanni Carta

Last

Conceptualization

2018-01-01

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Abstract

Background: Diagnosing people during the prodromal phase of an incipient psychosis can improve the chance of better outcome. In busy clinical settings, the ideal tool is a brief, easy-to-complete self-report questionnaire. Objective: To test the psychometric properties of the Italian version of one of the most used screening tools for the identification of the risk of psychosis, the Prodromal Questionnaire-Brief (PQ-B). Methods: Cross-sectional design. A convenience sample of college students was enrolled via snowball procedure (n=243; men: 45%). After understanding and signing the consent form, the participants received a booklet containing the following questionnaires: the 21-item Prodromal Questionnaire-Brief (PQ-B); the 12-item General Health Questionnaire (GHQ-12), and the 74-item Schizotypal Personality Questionnaire (SPQ). Receiver operating characteristic (ROC) analysis was used to assess the capacity of the PQ-B to identify individuals at risk of psychosis as independently defined based on the combination of GHQ-12 and SPQ thresholds. Results: The Italian version of the PQ-B revealed good internal consistency, test-retest reliability, and adequate convergent and divergent validity. The Youden method retrieved a cut-off = 7 for the PQ-B frequency score and a cut-off = 22 for the PQ-B distress score. Both PQ-B scores had a perfect (99%) negative predictive value. Conclusion: The PQ-B is a promising screening tool in two-stage protocols. The major advantage of the PQ-B is to exclude cases that are unlikely to be at risk of psychosis.