Peer victimisation during adolescence and its impact on depression in early adulthood: prospective cohort study in the United KingdomBMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h2469 (Published 02 June 2015) Cite this as: BMJ 2015;350:h2469
- Lucy Bowes, Leverhulme early career research fellow1,
- Carol Joinson, senior lecturer2,
- Dieter Wolke, professor3,
- Glyn Lewis, professor and chair in clinical trials and applied epidemiology4
- 1Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK
- 2Centre for Academic Mental Health, School of Social and Community Medicine, University of Bristol, Bristol, UK
- 3Department of Psychology and Division of Mental Health and Wellbeing, University of Warwick, Coventry, UK
- 4Division of Psychiatry, Faculty of Brain Sciences, University College London, London, UK
- Correspondence to: L Bowes
- Accepted 30 March 2015
Objective To investigate the strength of the association between victimisation by peers at age 13 years and depression at 18 years.
Design Longitudinal observational study.
Setting Avon Longitudinal Study of Parents and Children, a UK community based birth cohort.
Participants 6719 participants who reported on peer victimisation at age 13 years.
Main outcome measures Depression defined according to international classification of diseases, 10th revision (ICD-10) criteria, assessed using the clinical interview schedule-revised during clinic assessments with participants when they were aged 18 years. 3898 participants had data on both victimisation by peers at age 13 years and depression at age 18 years.
Results Of the 683 participants who reported frequent victimisation at age 13 years, 101 (14.8%) were depressed according to ICD-10 criteria at 18 years; of the 1446 participants reporting some victimisation at age 13 years, 103 (7.1%) were depressed at age 18 years; and of the 1769 participants reporting no victimisation at age 13 years, 98 (5.5%) were depressed at age 18 years. Compared with children who were not victimised those who were frequently victimised by peers had over a twofold increase in odds of depression (odds ratio 2.96, 95% confidence interval 2.21 to 3.97, P<0.001). This association was slightly reduced when adjusting for confounders (2.32, 1.49 to 3.63, P<0.001). The population attributable fraction suggested that 29.2% (95% confidence interval 10.9% to 43.7%) of depression at age 18 years could be explained by peer victimisation if this were a causal relation.
Conclusion When using observational data it is impossible to be certain that associations are causal. However, our results are consistent with the hypothesis that victimisation by peers in adolescence is associated with an increase in the risk of developing depression as an adult.
We thank the families who took part in this study, the midwives for help in recruiting them, and the ALSPAC team, which includes interviewers, computer and laboratory technicians, clerical workers, research scientists, volunteers, managers, receptionists, and nurses.
Contributors: LB and GL conceived and designed the study, with advice from CJ and DW. LB analysed the data, and LB, CJ, DW and GL interpreted the data. LB drafted the manuscript. CJ, DW, and GL criticised the manuscript for important intellectual content. All authors have read and approved the final version of the manuscript. This article is the work of the authors. LB serves as guarantor for the contents of this article. All authors, external and internal, had full access to all of the data (including statistical reports and tables) in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis. All researchers are independent of the funding bodies.
Funding: The UK Medical Research Council and the Wellcome Trust (grant reference 092731) and the University of Bristol provide core support for ALSPAC. This research was specifically funded by a Wellcome Trust grant held by GL (grant reference 084268/Z/07/Z). LB was partly supported by a grant from the Jacobs Foundation, and is supported by a Leverhulme Trust Early Career Fellowship; DW was partly supported by grant ES/K003593/1 of the Economic and Social Research Council.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, and no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: This study was approved by the ALSPAC Law and Ethics Committee and the local research ethics committees.
Data sharing: The ALSPAC policy on data sharing is available at www.bristol.ac.uk/alspac. To discuss access to ALSPAC data, please contact the ALSPAC executive team at .
Transparency: The lead author (LB) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.
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