Young for one's grade: A risk factor for psychotic experiences among adults in the National Comorbidity Survey-Replication

School-related difficulties have received relatively little attention as environmental risk factors for psychotic experiences (PEs), despite being characterized by marginalization and social defeat during critical periods of psychological development. This study examined both childhood age relative to one's classmates and school mobility as risk factors for adult psychotic experiences in the National Comorbidity Survey-Replication (NCS-R). Weighted logistic regression models were used to explore the hypotheses that lifetime psychotic experiences reported on the World Health Organization psychosis screen would be more prevalent among those younger than their classmates during childhood and for those with frequent school mobility. Younger perceived relative age (odds ratio (OR)=2.05, 95% confidence interval=1.43-2.95) was independently associated with psychotic experiences in the fully adjusted model, but school mobility was not. School-related risk factors for psychosis provide promising points for community-level intervention, and support the claim that environmental factors characterized by disadvantage and marginalization contribute to psychosis etiology.