M30. THE ASSOCIATION OF PEER-REPORTED BULLYING AND SOCIAL NETWORK CHARACTERISTICS WITH PSYCHOTIC EXPERIENCES IN CHILDHOOD
Authors: Steenkamp Lisa , Tiemeier Henning , Bolhuis Koen , Hillegers Manon , Kushner Steven A , Blanken Laura 
Published: May 2020

Abstract

Background
Psychotic experiences (PEs) are common in childhood and predictive of poor mental health outcomes, including psychosis, depression, and suicidal behavior. Prior studies indicate that bullying involvement and peer relationship difficulties may be linked to increased risk of PEs. However, most studies relied on self-report measures, while an approach including peer-report measures provides a more valid and comprehensive assessment of bullying and social relationships. This study aimed (1) to examine the prospective association of bullying perpetration and victimization with PEs in childhood, using a peer-nomination method complemented by ratings from mothers and teachers; (2) to investigate the prospective association between children’s social positions within classroom peer networks and PEs in childhood.

Methods
This study was embedded in the population-based Generation R Study, a birth cohort from Rotterdam, the Netherlands. Peer-reported bullying as well as peer rejection, peer acceptance, and prosocial behavior were obtained using dyadic peer nominations in classrooms, victimization was reported by the child itself (n=925, age=7.5). Bullying involvement was additionally assessed by teacher-reported questionnaire (n=1565, age=7.2) and mother-reported questionnaire (n=3276, age=8.1). Using network analysis, we constructed classroom peer networks for peer rejection, peer acceptance, and prosocial behavior and estimated children’s social positions within each network (i.e., degree centrality, closeness centrality and reciprocity). PEs were assessed at age 10 years with a self-report questionnaire. All analyses were adjusted for relevant potential confounders, including age, sex, ethnicity, and maternal education.

Results
After adjusting for sociodemographic covariates, higher bullying perpetration and higher victimization scores at 7–8 years were associated with increased risk of PEs at age 10 years for peer/self-report, teacher report, and mother report (bullying perpetration – peer report: OR=1.22, 95% CI 1.05–1.43, p=0.010, teacher report: OR=1.08, 95% CI 0.97–1.14, p=0.15, and mother report: OR=1.11, 95% CI 1.03–1.19, p=0.005; victimization – self report: OR=1.16, 95% CI 1.01–1.34, p=0.036, teacher report: OR=1.13, 95% CI 1.02–1.25, p=0.023, and mother report: OR=1.18, 95% CI 1.10–1.27, p&lt;0.001). Unfavorable positions within the peer rejection network were associated with increased risk of PEs (OR degree centrality=1.25, 95% CI 1.07–1.45, p FDR-corrected =0.036). After correction for multiple testing, there were no significant associations between social positions and PEs within the peer acceptance and the prosocial behavior networks.

Discussion
This is the first study to demonstrate that peer-reported bullying and peer rejection are associated with increased risk of PEs in childhood. Our findings extend current knowledge of self-perceptions in the context of psychosis vulnerability by offering unique insight into peer perceptions of bullying and social relationships. The consistent findings across child, mother, and teacher ratings provide important support for the role of bullying victimization and perpetration in the development of PEs. In addition, our findings showed that children with negative peer perceptions, i.e., children who are rejected by their peers, were at increased risk of PEs. School-based interventions aimed at preventing and eliminating bullying and social exclusion may help to prevent the development of PEs, and, hence, prevent the onset of severe mental health outcomes.