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Category: Project

Description: This study examined early risk factors for joint trajectories of bullying victimisation and perpetration using data from the Millennium Cohort Study (MCS) (N=14,525). Bullying victimisation and perpetration were assessed via child, mother, and teacher reports at ages 5, 7, 11, and 14 years. Early child and family risk factors were assessed at ages 9 months, 3, and 5 years. We applied a k-means clustering algorithm for longitudinal data (R package ‘KmL3D’) to derive developmental trajectories of bullying involvement across childhood and adolescence. We identified five joint trajectories: children who were uninvolved, early child victims, early adolescent victims, early child bullies, and bully-victims. Early individual vulnerabilities (e.g., male sex, emotional dysregulation, cognitive difficulties, and high BMI) and adverse family environments (e.g., maternal psychopathology, harsh discipline, and low family income) during the pre-school years independently forecasted multiple trajectories of bullying involvement. Here we have shared our analysis code in R Markdown format. Access to MCS data is available through the UK Data Service such that readers can replicate our study. Detailed information on the MCS can be found in the technical reports (https://cls.ucl.ac.uk/cls-studies/millennium-cohort-study/).