Bullying fosters interpersonal distrust and degrades adolescent mental health as predicted by Social Safety Theory.

Social Safety Theory predicts that socially threatening experiences such as bullying degrade mental health partly by fostering the belief that others cannot be trusted. Here we tested this prediction by examining how peer bullying in childhood impacted adolescent mental health, and whether this effect was mediated by interpersonal distrust and several other commonly studied mediators-namely diet, sleep and physical activity-in 10,000 youth drawn from the UK's Millennium Cohort Study. Youth bullied in childhood developed more internalizing, externalizing and total mental health problems in late adolescence, and this effect was partially mediated by interpersonal distrust during middle adolescence. Indeed, adolescents who developed greater distrust were approximately 3.5 times more likely to subsequently experience clinically significant mental health problems than those who developed less distrust. Individual and school-based interventions aimed at reducing the negative impact of bullying on mental health may thus benefit from bolstering youths' sense of trust in others.