Validation of the Prodromal Questionnaire–Brief in a representative sample of adolescents: Internal structure, norms, reliability, and links with psychopathology

Objectives The main purpose of the present study was twofold: to validate the Prodromal Questionnaire–Brief (PQ‐B) in a community‐derived sample of adolescents and to examine the links between psychotic‐like experiences and emotional and behavioral problems, prosocial behavior, suicidal ideation, and bipolar‐like experiences. Method One thousand five hundred eighty‐eight students selected by random sampling participated in a cross‐sectional survey. The PQ‐B, Paykel Suicide Scale, Strengths and Difficulties Questionnaire, Mood Disorder Questionnaire, Penn Matrix Reasoning Test, Family Affluence Scale‐II, and Oviedo Infrequency Scale were used. Results The unidimensional factorial structure of the PQ‐B items showed adequate goodness of fit index. This model also showed configural and strong invariance across gender. The internal consistency of the PQ‐B total frequency score was 0.92. A high degree of overlap was found between psychotic‐like experiences and emotional and behavioral problems, suicidal ideation, and bipolar‐like experiences. Conclusion The PQ‐B is a brief, easy, and reliable tool for screening psychotic‐like experiences in adolescents from the general population. The assessment of risk for psychosis and its relationship with other psychopathological risk factors in a close‐in strategy or two‐stage process model may help us to enhance the early identification for youths at heightened risk for serious mental disorders.