In a study in the journal Current Biology, researchers used brain scans to explore the impact of physical abuse or domestic violence on children's emotional development and found that exposure to it was linked to increased activity in two brain areas when children were shown pictures of angry faces.

Previous studies that scanned the brains of soldiers exposed to violent combat situations showed the same pattern of heightened activity in these two brain areas -- the anterior insula and the amygdala -- which experts say are associated with detecting potential threats.

This suggests that both maltreated children and soldiers may have adapted to become "hyper-aware" of danger in their environment, the researchers said.

"Enhanced reactivity to a...threat cue such as anger may represent an adaptive response for these children in the short term, helping keep them out of danger," said Eamon McCrory of Britain's University College London, who led the study.

But he added that such responses may also be underlying neurobiological risk factor which increases the children's susceptibility to later mental illness like depression.

Depression is already a major cause of mortality, disability, and economic burden worldwide and the World Health Organization predicts that by 2020, it will be the second leading contributor to the global burden of disease across all ages.

Childhood maltreatment is known to be one of the most potent environmental risk factors linked to later mental health problems such as anxiety disorders and depression.