The brains of kids who have a high risk of depression because they have parents with depression are structurally different from other kids’ brains, a new study finds.

Depression often first appears during adolescence. Having a parent with depression is one of the biggest known risk factors. Teens whose parents have depression are two to three times more likely to develop depression than other teens, research shows.

But the brain mechanisms behind this family risk are unclear.

To learn more, Columbia University researchers analysed brain images from more 7 000 children. They described it as the largest study of its kind done in the United States.

About one-third of the kids were at high risk because they had a parent with depression. In those kids, a brain structure called the right putamen – which is linked to reward, motivation and the experience of pleasure – was smaller than in children of parents without a history of depression.

The study was published online recently in the Journal of the American Academy of Child & Adolescent Psychiatry.

“These findings highlight a potential risk factor that may lead to the development of depressive disorders during a peak period of onset,” senior author Randy Auerbach said in a university news release. He is an associate professor of medical psychology at Columbia’s College of Physicians and Surgeons, in New York City.

A transdiagnostic risk factor

Auerbach noted that prior research has linked smaller putamen volume to a reduced ability to experience pleasure, which is implicated in depression, substance use, psychosis and suicidal behaviours.

“Thus, it may be that smaller putamen volume is a transdiagnostic risk factor that may confer vulnerability to broad-based mental disorders,” he said.

Study leader David Pagliaccio, an assistant professor of clinical neurobiology, said that understanding differences in the brains of kids with familial risks may help identify those with highest odds for developing depression and could lead to improved treatment.

“As children will be followed for a 10-year period during one of the greatest periods of risk, we have a unique opportunity to determine whether reduced putamen volumes are associated with depression specifically or mental disorders more generally,” Pagliaccio said in the news release.

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