Is bullying in adolescence associated with the development of depressive symptoms in adulthood?: A longitudinal cohort study

BACKGROUND: Being bullied in adolescence is linked to mental health problems like anxiety, depressive- and somatic symptoms and can have negative consequences on both an individual and a societal level. However, evidence regarding the long-term mental health consequences of bullying in adolescence is limited. The aim of this study was to examine whether being bullied at age 15 or 18 was associated with experiencing depressive symptoms at age 28, and to examine whether being bullied at both ages 15 and 18 increased the risk of experiencing depressive symptoms at age 28. METHODS: A prospective cohort study, which applied data from the West Jutland Cohort Study, was conducted. Bullying and depressive symptoms were measured on the basis of self-reported data from surveys in 2004, 2007 and 2017. Depressive symptoms were measured with the Center for Epidemiological Studies Depression Scale. A total of 1790 participants were included in the study, and analyzed by multiple logistic regressions. RESULTS: The results showed associations between being bullied at age 15 or 18 and the reporting of depressive symptoms at age 28 when adjusted for potential confounders. An exposure–response relationship was seen in those who were bullied at both ages 15 and 18. This group had the highest risk of developing depressive symptoms at age 28. CONCLUSIONS: Being bullied in adolescence was associated with developing depressive symptoms in adulthood and there was an exposure–response relationship between being bullied over time and the later reporting of depressive symptoms. The results highlight the need to provide more detailed information to schools and local communities about the negative consequences of bullying. Such increased awareness may help reduce the risk of young people developing depressive symptoms later in life.