Bullying leaves mark on kids' psyches.

Between ages 5 and 7, being the victim of a bully at school uniquely contributes to a child's behavioral and emotional problems, according to observations of children before and after 2 years of bullying.

Youngsters targeted by bullies often enter school already showing signs of maladjustment, but those problems worsen and expand over 2 years of bullying, say psychologist Louise Arseneault of the Institute of Psychiatry in London and her colleagues.

The researchers studied 2,232 English and Welsh children born in 1994 and 1995. The sample consisted of pairs of healthy identical and fraternal twins. Experimenters obtained reports from mothers and teachers about the children's behavior problems and school adjustment at age 5 upon entry into school and again at age 7.

At the second assessment, mothers and teachers identified 272 children--14 percent of the sample--as being regularly excluded from groups and games, beaten up, or otherwise bullied. Another 137 kids--6 percent of the total--were both victims of bullies and bullies themselves. Arseneault's team compared these groups with 1,387 children who were neither victims nor perpetrators of bullying.

Compared with unbullied kids, those bullied by others displayed more social withdrawal, physical complaints, symptoms of anxiety and depression, and unhappiness at school at ages 5 and 7, the researchers report in the July Pediatrics.

Children who were both victims and practitioners of bullying had the highest rates of behavioral and emotional problems, as well as pronounced academic difficulties.

From age 5 to 7, signs of maladjustment substantially escalated in all bullied children. These findings emphasize the need for bullying-prevention programs (SN: 5/27/06, p. 328), the researchers contend. --B.B.