Italian validation of the "Early Recognition Inventory for the retrospective assessment of the Onset of Schizophrenia Checklist": Reliability, validity and instructions for use

Objectives: Screening questionnaires are often used at first-contact with psychiatric services to identify, among those displaying psychological distress, those who need more in-depth assessment. The Early Recognition Inventory for the retrospective assessment of the Onset of Schizophrenia Checklist (ERIraos-CL) may be a useful tool to prompt further screenings in young help-seekers, who are experiencing symptoms that are compatible with a prodromic state of psychosis. This study describes the psychometric proprieties of the Italian version of ERIraos-CL in high risk and early onset populations. Materials and methods: The study was carried out as part of Programma2000 in Milan (Italy). Participants were 113 individuals with a diagnosis of First Episode Psychosis (FEP) and 97 individuals with a diagnosis of high-risk psychosis (UHR). The ERIraos-CL reliability was measured by internal consistency (Cronbach alpha) and by test-retest stability after 6 months (intraclass correlation coefficient). The concurrent validity of ERIraos-CL was assessed by correlation with the Brief Psychiatric Rating Scale (BPRS) and with the Health of the Nation Outcome Scales (HoNOS). The discriminant validity of this tool was assessed by comparing scores between FEP and URP with threshold at 10, which is slightly less than the threshold that discriminates between at risk cases and non-cases (12). Results: Internal consistency was good for all the scales in both samples, with low values for ERIraos-CL. Retest stability after 6 months of ERIraos-CL was acceptable (> 0.70) in both diagnostic groups. In both groups, ERIraos-CL correlated positively with HoNOS and BPRS. ERIraos-CL discriminates effectively between FEP and UHR. The two groups differ statistically by symptoms that qualify for the presence of an active episode of psychosis: suspiciousness/distrust, ideas of self-reference, changes in perception, paranoid ideation and hallucinations. Conclusions: The Italian version of the ERIraos-CL has good psychometric properties that make it suitable for routine use as a scale for the identification of the cases that might benefit from a more in-depth assessment of the risk of psychosis.