MedicalResearch.com Interview with:
Dr. Lucy Bowes Ph.D
Leverhulme Early Career Research Fellow
Fellow of Magdalen College
Department of Experimental Psychology
University of Oxford Oxford
Medical Research: What is the background for this study? What are the main findings?
Response: Major depression is a severe mental illness, and a leading contributor to the global burden of disease. Rates of depression begin to rise in the teenage years, though the reasons for this remain unclear. Peers become particularly important during this time, and victimisation by peers or “
bullying” has been proposed as one potentially modifiable risk factor for depression. There are robust findings that peer victimisation in childhood is associated with short-term internalizing symptoms, however it remains unclear whether victimization in the teenage years is associated with major depression. Only a relatively small number of longitudinal studies have prospectively investigated victimisation in relation to depression meeting diagnostic criteria in late adolescence or adulthood. Limitations of these studies include poor measures of bullying, lack of adjustment for key confounders such as baseline emotional and behavioral difficulties and child maltreatment.
Our prospective cohort observational study, published in The BMJ, used detailed self-report data on peer victimisation at 13 years from 6,719 participants of the ALSPAC or ‘Children of the 90s’ study. The outcome was depression at 18 years, measured using a self-administered computerised version of the Clinical Interview Schedule Revised, CIS-R (data available for 3,898 participants). We adjusted for a range of confounders including baseline emotional and behavioral problems, family background and other risk factors. Of the 683 children who reported frequent victimisation at 13 years, 101 (14.8%) were depressed at 18 years. Of the 1,446 children reporting some victimisation, 103 (7.1%) were depressed, and of the 1,769 children reporting no victimisation at 13 years, 98 (5.5%) were depressed. Children who were frequently
victimized had over a two-fold increase in odds of depression compared with children who were not victimized by peers. This association was slightly reduced when adjusting for key confounders. The population attributable fraction suggested that 29% of depression at 18 could be explained by peer victimisation if this were a causal relationship.
