Being bullied in childhood has a greater negative impact on teenager's mental health than being maltreated , according to new research published in The Lancet Psychiatry journal.
The findings show that individuals who are bullied in childhood are around five times more likely to experience anxiety (odds ratio 4.9) and are nearly twice as likely to report more depression and self-harm at age 18 (odds ratio 1.7) than children who are maltreated.
The study, led by Professor Dieter Wolke from the University of Warwick, UK, is the first of its kind to directly compare the effects of maltreatment (by adults) and peer bullying in childhood on mental health outcomes (ie, anxiety, depression, self-harm, suicidal tendencies) in young adulthood.
The findings come from the UK Avon Longitudinal Study of Parents and Children (ALSPAC) and the Great Smoky Mountain Studies in the USA (GSMS). The current study includes 4026 children from ALSPAC whose parents provided information on maltreatment between the ages of 8 weeks and 8.6 years, and their child's reports of bullying when they were aged 8, 10, and 13; and 1420 children from GSMS who reported information on maltreatment and bullying between the ages of 9 and 16.
The harmful effects of bullying remained even when other factors that are known to increase the risk of child abuse and bullying, including family hardship and the mental health of mothers, were taken into account.
According to Professor Wolke, "Until now, governments have focused their efforts and resources on family maltreatment rather than bullying. Since 1 in 3 children worldwide report being bullied, and it is clear that bullied children have similar or worse mental health problems later in life to those who are maltreated, more needs to be done to address this imbalance. Moreover, it is vital that schools, health services, and other agencies work together to tackle bullying." 
Writing in a linked Comment, David Finkelhor and Corinna Jenkins Tucker from the University of New Hampshire, Durham, USA discuss the fragmented response to child maltreatment and the need for protection lobbies to join forces, saying that, "This new study illustrates the growing consensus that children are entitled to grow up free from violence, denigration, and non-consented sexual activity at the hands of both adults and young peers. That growing consensus might be responsible for the fact that, if the epidemiological data are to be trusted, in spite of the fragmentations of response systems, the toll of some of these various scourges seems to be on the decline in the past 20 years."
The research is being presented at the Pediatric Academic Societies (PAS) annual meeting in San Diego, USA. Professor Wolke will also give a talk covering this research at The Times Cheltenham Science Festival , UK, in June.
NOTES TO EDITORS:
This study was funded by the Wellcome Trust, Medical Research Council, Economic and Social Research Council, National Institute of Mental Health, the National Institute on Drug Abuse, NARSAD (Early Career Award), and the William T Grant Foundation.
 Child maltreatment is defined as any physical or emotional ill-treatment, sexual abuse, neglect, or negligent treatment resulting in actual or potential harm to the child's health, survival, or dignity.
 Quote direct from author and cannot be found in text of Article.