The Impact of the Magnitude of the Group of Bullies on Health-Related Quality of Life and Academic Performance Among Adolescents.

This study examines the consequences that physical and verbal/social victimization by peers and the magnitude of the groups of bullies have on academic performance and the psychological and social domains of Health-related Quality of Life (HRQoL). 1428 secondary school students in the south-east Spain completed the Spanish version of the "Adolescent Peer Relations Instrument-Bullying" and "KIDSCREEN-52" questionnaires in order to analyse, respectively, peer victimization and the psychological and social domains of HRQoL. Data on sociodemographic characteristics and academic achievement was also collected. Findings emphasise the potential of peer victimization in all its forms as risk factors explaining poor HRQoL in psychological, social and emotional domains. The number of bullies was an imponent and significant risk factor that explains a worse HRQoL in the five socio-psychological dimensions studied (Odds Ratio 4.08, Odds Ratio 9.25, Odds Ratio 4.69, Odds Ratio 2.91, Odds Ratio 11.92). Nevertheless, peer victimization rarely seems to affect academic achievement. Results suggest that much of prevention and intervention are still needed to reduce peer victimization, focusing on large bullies' groups and their harmful impact on adolescent's HRQoL.