Psychosis risk screening: Validation of the youth psychosis at-risk questionnaire - brief in a community-derived sample of adolescents.

There have been several attempts to identify individuals potentially at high risk for psychotic-spectrum disorders using brief screening measures. However, relatively few studies have tested the psychometric properties of the psychosis screening measures in representative samples of adolescents. The main purpose of the present study was to analyse the prevalence, factorial structure, measurement invariance across gender, and reliability of the Youth Psychosis At-Risk Questionnaire - Brief (YPARQ-B) in a community-derived sample of adolescents. Additionally, the relationship between YPARQ-B, depressive symptoms, psychopathology, stress manifestations, and prosocial skills was analysed. One thousand and twenty students from high schools participated in a cross-sectional survey. The YPARQ-B, the Reynolds Adolescent Depression Scale, the Strengths and Difficulties Questionnaire, and the Student Stress Inventory - Stress Manifestations were used. A total of 85.1% of the total sample self-reported at least one subclinical psychotic experience. We observed a total of 10.9% of adolescents with a cutoff score of ≥11 or 6.8% with a cutoff score of ≥13. The analysis of internal structure of the YPARQ-B yielded an essentially unidimensional structure. The YPARQ-B scores showed measurement invariance across gender. The internal consistency of the YPARQ-B total score was 0.94. Furthermore, self-reported subclinical psychotic experiences were associated with depressive symptoms, emotional and behavioural problems, poor prosocial skills, and stress manifestations. These results would appear to indicate that YPARQ-B is a brief and easy tool to assess self-reported subclinical psychotic experiences in adolescents from the general population. The assessment of these experiences in community settings, and its associations with psychopathology, may help us to enhance the possibility of an early identification of adolescents potentially at risk for psychosis and mental health problems.