A brain region that processes emotions works differently in pre-schoolers with depression than in those without the mental health disorder, a new study shows.
The findings could lead to ways to identify and treat depressed children earlier in the course of the illness, potentially preventing problems later in life, according to the researchers at Washington University School of Medicine in St Louis.
"The findings really hammer home that these kids are suffering from a very real disorder that requires treatment," lead author Michael Gaffrey, an assistant professor of psychiatry, said in a university news release.
"We believe this study demonstrates that there are differences in the brains of these very young children and that they may mark the beginnings of a lifelong problem," he added.
The researchers used functional MRI to assess brain activity in 54 children, aged 4 to 6, including 23 who had been diagnosed with depression. None of the children in the study had taken antidepressant medications.
The children with depression had elevated activity in the amygdala, a part of the brain that processes emotions, according to the study, published in the July issue of the Journal of the American Academy of Child & Adolescent Psychiatry.
Previous research found similar changes in the amygdala in adults, adolescents and older children with depression.
While in the fMRI scanner, the children were shown pictures of people with happy, sad, fearful and neutral facial expressions.
"The amygdala region showed elevated activity when the depressed children viewed pictures of people's faces," Gaffrey said. "We saw the same elevated activity, regardless of the type of faces the children were shown. So it wasn't that they reacted only to sad faces or to happy faces, but every face they saw aroused activity in the amygdala."
The Nemours Foundation has more about depression in children.