Objective
Among current early screeners for psychosis-risk states, the Prodromal Questionnaire-16 items (PQ-16) is used. We aimed to assess reliability of the Italian version of the PQ-16 in a young help-seeking sample.
Methods
We included 151 individuals, aged 13-35 years, seeking help at the Reggio Emilia outpatient mental health services in a large semirural catchment area (550.000 inhabitants). Participants completed the Italian version of the PQ-16 (iPQ-16) and were subsequently evaluated with the Comprehensive Assessment of At-Risk Mental States (CAARMS). We examined test-retest reliability, internal consistency and diagnostic accuracy (i.e. sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios) between PQ-16 and CAARMS UHR-defined criteria using coefficient of stability (k), Cronbach’s alpha and Cohen’s kappa, respectively.
Results
The iPQ-16 showed excellent short term test-retest reliability (k = 0.898), high internal consistency (α = 0.810) and acceptable diagnostic accuracy (sensitivity = 73.5% and specificity = 75.9% at the proposed cut-off of ≥ 6 on symptom total score).
Conclusions
Psychometric properties of the iPQ-16 were satisfactory. The iPQ-16 is a suitable screening tool for routine use in mental health care services. Indeed, it is short and therefore easy to implement in routine assessment.