(Reuters Health) - Children who are bullied by their peers may be more likely to suffer mental health problems later in life than kids who are abused by adults, a study suggests.

Previous research has linked physical, emotional and sexual abuse during childhood to psychological difficulties later in life. Bullying too can have severe, long-lasting psychological and physical effects.

For the new study, researchers looked for associations between maltreatment, being bullied, and long term mental health problems. In particular, they say, they wanted to know whether mental health problems in kids exposed to those kinds of experiences are due to both maltreatment and bullying or whether bullying has a unique effect.

"We found, somewhat surprisingly, that those who were bullied and maltreated were not at higher risk than those just bullied," senior study author Dieter Wolke, a psychology professor at the University of Warwick in the U.K., said by email.

The data came from two large studies that tracked mental health in children and then followed them at least until at least age 18. One study, from the U.S., included more than 1,200 participants. The other, from the U.K., involved more than 4,000.

Both studies relied on a combination of interviews with parents to track abuse in younger children as well as reports of bullying by older children.

As young adults, 19 percent in the U.K. group and 18 percent in the U.S. group had mental health issues such as depression, anxiety and suicidal thoughts.

After adjusting for other family factors that might contribute to psychological problems, the researchers found an increased risk of depression among abused children in the U.S. group but not in the U.K. group.

In both groups, however, mental health problems were significantly more likely in children who were bullied by their peers than in kids who were abused.

It's possible that abuse was underreported by parents questioned about treatment of their children, the researchers note in the study, published in The Lancet Psychiatry and presented today at the Pediatric Academic Societies annual meeting in San Diego. The study also didn't explore the severity of abuse or the age at which it began.

Even so, the findings highlight the need for parents, educators and clinicians to pay closer attention to bullying, Wolke said.

"It is particularly novel that they found bullying is a greater source of mental health problems than maltreatment," said Catherine Bradshaw, deputy director of the Johns Hopkins Center for the Prevention of Youth Violence in Baltimore.

Given this emerging connection, parents whose children encounter behavior problems at school should be sure to follow up to make sure bullying isn't a factor, said Bradshaw, who wasn't involved in the study. At the same time, schools officials who discover bullying should explore whether there might be problems at home.

Teaching good communication and conflict resolution skills before kids reach school age is also important for prevention, she said. Later on, schools should reenforce these skills by creating a strong sense of community and fostering an environment where students feel connected to one another as well as to teachers and other adults.

"Schools often become the outlets where bullying comes to a head," Bradshaw said. "Creating a sense of belonging has been consistently shown to be a protective factor as have programs that improve the school climate."

SOURCE: http://bit.ly/1lNlf0J The Lancet Psychiatry, online April 28, 2015.

(By Lisa Rapaport)