MONDAY, Nov. 3 (HealthDayNews) -- Children whose mothers suffer depression after childbirth face a greater risk of violent behavior by the time they reach age 11.

That disturbing conclusion is made in a British study in the November issue of Developmental Psychology.

The risk of violent behavior among such children is especially high if their mothers suffered repeated bouts of depression.

The study also found that, compared to their peers, children with mothers who'd been depressed at three months after birth had more diverse and severe aggressive behavior.

Researchers examined 122 families in two South London communities. Mothers were interviewed while they were pregnant, at three months postpartum, and again when the child was 1, 4 and 11 years old. Mothers, teachers and children were interviewed about violent behavior when the child was 11.

More violent behavior was identified in children whose mothers had been depressed in the months following childbirth, especially if depression occurred at three months postpartum and at least once again after that.

Violence was more common in boys than girls at age 11 and mostly involved fighting with peers. The fighting often resulted in injury and suspension from school.

The link between a child's violent behavior and the mother's postpartum depression was associated with the children's problems in regulating their attention and emotion, the study says. These children were angry and inattentive at age 11 and these characteristics were linked to their increased risk of violent behavior.

"Previous research has found that problems in regulating one's attention and activity and in managing anger and responses to frustration are associated with violent behavior and various disruptive behavior disorders, and our study suggests that this is what is taking place here," researcher Dale F. Hay of Cardiff University says in a prepared statement.

He and his colleagues concluded that this and other studies clearly show that a mother's mental state after childbirth is an easily identifiable risk factor for a child's intellectual and social development.

More information

Here's where you can learn more about aggressive behavior in children.