An Item Response Theory Analysis of the Prodromal Questionnaire-Brief Child Version: Developing a Screening Form That Informs Understanding of Self-Reported Psychotic-Like Experiences in Childhood

The Prodromal Questionnaire-Brief Child Version (PQ-BC) has been developed as a tool for identifying psychotic-like experiences (PLEs) in school-age children. The current study examined the psychometric properties of the PQ-BC, examined how well the PQ-BC estimates the latent construct of PLEs (θ), and began the process of developing a screening form informed by item response theory (IRT). Utilizing the baseline (N = 11,129) sample from the Adolescent Brain Cognitive Development study, we examined which PQ-BC items provide the most information and best discriminate individuals experiencing PLEs. Using hierarchical linear models (HLMs), we found that θ scores were significantly associated with several previously identified predictors of psychosis spectrum symptoms (i.e., history of psychosis, internalizing symptoms, cognitive impairments, developmental milestone delays, and resting-state functional connectivity impairments) at baseline and Year 1 (n = 5,532). Using item-level information and discrimination parameters of the PQ-BC from the baseline sample, we created a 7-item screening form. HLMs generally found significant associations between screening form scores for both baseline and Year 1 with the aforementioned predictors. The analyses provide evidence for the validity of a screening form derived from the PQ-BC using IRT-derived parameters. This screening form could prove useful when the full measure is not feasible.