We analyzed a population-based cohort of 11,780 US children to identify risk and protective factors by kindergarten predictive of being frequently verbally, social, reputationally, or physically victimized during the upper elementary grades. We also stratified the analyses by biological sex. Kindergarten children displaying externalizing problem…

The present study examined, within a longitudinal family-informed design and across middle childhood, the predictive associations between preference for solitude and social wariness, two forms of social withdrawal, and peer difficulties. Specifically, preference for solitude, rather than social wariness, was expected to predict peer victimization…

This study assessed the genetic and environmental contributions to peer difficulties in the early school years. Twins' peer difficulties were assessed longitudinally in kindergarten (796 twins, "M"[subscript age] = 6.1 years), Grade 1 (948 twins, "M"[subscript age] = 7.1 years), and Grade 4 (868 twins, "M"[subscript…