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 (θˆ), 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 θˆ 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.