Researchers followed the mental health of more than 4,000 children in Avon, south west England from birth to age 18 and 1,400 others in North Carolina from age nine up to age 26 through parent questionnaires and clinical interviews.
In the Avon study, maltreatment was defined as physical, emotional, or sexual abuse or "maladaptive parenting" such as hitting, shouting and hostility. Children were interviewed about the frequency of bullying, which included overt threats, physical violence and nasty names as well as social exclusion or spreading lies or rumours.
The results consistently showed an increased risk of anxiety, depression, self-harm and suicidal tendencies in children who were bullied, whether or not they had a history of abuse by adults, Prof. William Copeland, a clinical psychologist at Duke University School of Medicine in Durham, N.C. and his co-authors concluded in Tuesday's issue of Lancet Psychiatry.
"What was a surprise was to see [the results] were as significant and pervasive as what we see for children that are physically abused, sexually abused or neglected," Copeland said.
Government policies have focused almost exclusively on providing services for child abuse but much less attention and resources are devoted to bullying, the researchers said.
Copeland's previous research showed long-term repercussions from bullying persist -- and that includes impacts on physical health, dropping out of school and trouble with authorities.
Bullying not a harmless rite of passage
Antibullying programs can be adopted by schools with more resources, Copeland said. But first, everyone from parents to school administrators need to stop downplaying the repeated humiliation of bullying as a rite as passage. Then the first focus should be on prevention as well as validating a child's experience, stopping the bullying and offering services in school when needed.
The harmful effects of persistent bullying remained after researchers took into account other factors that are known to increase the risk of child abuse and bullying, such as family hardship and the mental health of mothers.
In both groups of children, about 40 per cent of children who were maltreated were also bullied.
Bulllying can be seen as both a consequence and a cause or risk factor for later mental health problems. As for why maltreatment didn't show an association, the study's authors speculated the time lag between maltreatment and depression, for example, could be playing a role. It's also possible the catch-all category of maltreatment obscured associations with specific types of abuse, such as sexual and emotional abuse, the study's authors said.
The drawbacks of the research include how parents could underreport maltreatment. Cyberbullying, which previous studies overlaps with traditional bullying, wasn't considered. Not all of the children in the Avon study completed the mental health questionnaire. Also, the U.S. sample wasn't representative of the whole country.
Foster best environment for all children
In a journal editorial published with the study, David Finkelhor and Corinna Jenkins Tucker from the University of New Hampshire, Durham, cautioned the finding on the influence of maltreatment by adults is contradicted by at least one other long-term direct comparison with bullying and a large body of research on the enduring and damaging effects of caregiver abuse.
"The key questions become not 'Is it worse to be battered by your dad or bullied by your buddy?" but rather 'How do children respond to or cope with violence and degradation at different stages of their development?'" and how can these negative impacts be better mitigated, the editorial said.
The editorial writers said the new study illustrated the growing consensus that children are entitled to grow up free from violence, denigration and non-consensual sexual activity at the hands of both adults and young peers.
Dr. Stan Kutcher, a professor in the psychiatry department at Dalhousie University in Halifax cautioned the two datasets were developed and applied differently. Kutcher would like to see more details on how the intensity, severity and persistence of bullying were associated with emotional difficulties later in life.
"I think we as a society need to work to ensure that the social fabric has woven into every single aspect the best conditions that we can create to help our young people grow and develop to be the best they can be," Kutcher said from Toronto.
While most young people in Canada enjoy flourishing mental health, Kutcher said, interventions are needed in both the early years as well as during adolescence to help those who need it.
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.