Defective Processing Speed and Nonclinical Psychotic Experiences in Children: Longitudinal Analyses in a Large Birth Cohort

OBJECTIVE: Psychotic experiences in children are associated with an elevated risk of developing psychosis. The authors investigated whether the pattern of cognitive deficits present in psychosis also exists in children with psychotic experiences within the general population. METHOD: The authors examined the longitudinal relationships between key cognitive domains, selected a priori based on their association with schizophrenia, and onset of psychotic experiences in children from the Avon Longitudinal Study of Parents and Children and whether these associations were independent of one another. RESULTS: Lower performance in the domains of processing speed at age 8 years (odds ratio=1.24, 95% CI=1.12–1.36) and attention at age 11 (odds ratio=1.14, 95% CI=1.04–1.25) were associated with higher risk of psychotic experiences at age 12. When adjusting for the other cognitive domains, processing speed at age 8 (odds ratio=1.20, 95% CI=1.09–1.33) was the measure most strongly associated with psychotic experiences. CONCLUSIONS: Defective processing speed is a particularly strong predictor of psychotic experiences in children. Furthermore, the pattern of associations between cognition and psychotic experiences in children within the general population is similar to the one between cognition and schizophrenia. These findings have potentially important implications for understanding the pathogenesis of psychotic disorders and the specific deficits that seem to place children at higher risk of psychopathology.