Lorenzo Pelizza1, Silvia Azzali1, Federica Paterlini1, Ilaria Scazza1, Sara Garlassi1, Luigi Rocco Chiri2, Michele Poletti1, Simona Pupo3, Andrea Raballo4,5. 1. Department of Mental Health and Pathological Addiction, Reggio Emilia Public Health Care Centre, Reggio Emilia, Italy. 2. Department of Mental Health and Pathological Addiction, Bologna Public Health Care Centre, Bologna, Italy. 3. Intensive Care Unit, Guastalla Civil Hospital, Reggio Emilia Public Health Care Centre, Guastalla, Italy. 4. Department of Psychology, Childhood and Development Research Group, Norwegian University of Science and Technology (NTNU), Bygg 12, 318, Dragvall, Trondheim, Norway. 5. Department of Medicine, Division of Psychiatry, Clinical Psychology and Rehabilitation, University of Perugia, Santa Maria della Misericordia, Edificio Ellisse, Sant'Andrea delle Fratte, Perugia, Italy.
Abstract
BACKGROUND: The Brief, 21-item version of the Prodromal Questionnaire (PQ-B) is a promising screener for psychosis-risk states that could be implemented in routine clinical practice. In this study, we assessed psychometric properties of the Italian version of the PQ-B (iPQ-B) in a sample of 243 help-seekers, aged 13-35 years. SAMPLING AND METHODS: After completing the iPQ-B, participants were assessed with the Comprehensive Assessment of At-Risk Mental States (CAARMS). Diagnostic accuracy (sensitivity, specificity, positive and negative predictive values [PPV and NPV], positive and negative likelihood ratios) and concurrent validity between PQ-B and CAARMS were determined using Cronbach's alpha and Cohen's kappa. We also tested the validity of the adopted PQ-B cut-offs through Receiver Operating Characteristic (ROC) curves plotted against CAARMS diagnoses and the predictive validity of the iPQ-B at 1-year follow-up. RESULTS: The iPQ-B showed high internal consistency (Cronbach's alpha = 0.868), acceptable diagnostic accuracy and concurrent validity (70% sensitivity, 67% specificity, 81% PPV, Cohen's kappa = 0.335). ROC analyses pointed to threshold of ≥20 on the PQ-B total distress score as best cut-off. After 12 months of follow-up, 11% of participants who scored ≥4 on the PQ-B distressing item total score and did not meet CAARMS psychosis criteria at baseline, developed a psychotic disorder. Interestingly, age had significant negative correlations with iPQ-B scores and adolescents (aged < 18 years) showed higher iPQ-B scores than young adults. CONCLUSIONS: Overall, the psychometric properties of the iPQ-B were satisfactory. As iPQ-B scores appeared inversely associated to age, age-tailored cut-off scores are recommended for screening purposes in child-adolescent cohorts.
BACKGROUND: The Brief, 21-item version of the Prodromal Questionnaire (PQ-B) is a promising screener for psychosis-risk states that could be implemented in routine clinical practice. In this study, we assessed psychometric properties of the Italian version of the PQ-B (iPQ-B) in a sample of 243 help-seekers, aged 13-35 years. SAMPLING AND METHODS: After completing the iPQ-B, participants were assessed with the Comprehensive Assessment of At-Risk Mental States (CAARMS). Diagnostic accuracy (sensitivity, specificity, positive and negative predictive values [PPV and NPV], positive and negative likelihood ratios) and concurrent validity between PQ-B and CAARMS were determined using Cronbach's alpha and Cohen's kappa. We also tested the validity of the adopted PQ-B cut-offs through Receiver Operating Characteristic (ROC) curves plotted against CAARMS diagnoses and the predictive validity of the iPQ-B at 1-year follow-up. RESULTS: The iPQ-B showed high internal consistency (Cronbach's alpha = 0.868), acceptable diagnostic accuracy and concurrent validity (70% sensitivity, 67% specificity, 81% PPV, Cohen's kappa = 0.335). ROC analyses pointed to threshold of ≥20 on the PQ-B total distress score as best cut-off. After 12 months of follow-up, 11% of participants who scored ≥4 on the PQ-B distressing item total score and did not meet CAARMS psychosis criteria at baseline, developed a psychotic disorder. Interestingly, age had significant negative correlations with iPQ-B scores and adolescents (aged < 18 years) showed higher iPQ-B scores than young adults. CONCLUSIONS: Overall, the psychometric properties of the iPQ-B were satisfactory. As iPQ-B scores appeared inversely associated to age, age-tailored cut-off scores are recommended for screening purposes in child-adolescent cohorts.