New research suggests that bullying adversely affects children in later life more than being maltreated.

Researchers at the University of Warwick found that found that children who have bullied by peers suffer worse in the longer term than those who have been maltreated by adults.  Previous studies have already established a link between maltreatment by adults and the mental health consequences for children.

For the study, researchers examined whether long-term mental health issues among victims of bullying were related to having been maltreated by adults as well. They collected and analyzed data from more than 4,000 people in the UK ALSPAC study and more than 1,000 participants from the US Great Smoky Mountain Study.

They looked at reports of maltreatment between the ages of 8 weeks and 8.6 years; bullying at ages 8, 10 and 13; and mental health outcomes at age 18. Data from the Great Smoky Mountain Study had reports of maltreatment and bullying between the ages of 9 and 16, and mental health outcomes from 19 to 25 years old.

"The mental health outcomes we were looking for included anxiety, depression or suicidal tendencies. Our results showed those who were bullied were more likely to suffer from mental health problems than those who were maltreated," Dieter Wolke, who led the study, said in a statement. "Being both bullied and maltreated also increased the risk of overall mental health problems, anxiety and depression in both groups."

They found that only 8.5 percent of the children who participated in the ALSPAC study reported maltreatment, 29.7 percent reported bullying and 7 percent reported both maltreatment and bullying. In the Great Smoky Mountain Study, 15 percent reported maltreatment, 16.3 percent reported bullying and 9.8 percent reported maltreatment and bullying.

"Being bullied is not a harmless rite of passage or an inevitable part of growing up; it has serious long-term consequences. It is important for schools, health services and other agencies to work together to reduce bullying and the adverse effects related to it," Wolke said.

The findings will be presented at the Pediatric Academic Societies (PAS) annual meeting in San Diego.