A test, which could help detect the people who are vulnerable to developing depression, could be available within a decade.
Researchers, including Dr Kerry Ressler of Emory University, Dr Rebekah Bradley of the Atlanta VA Medical Centre and others, have discovered resilient variants of a gene that may help prevent childhood abuse and stress from developing into adult depression.
Certain variations in a gene that helps regulate response to stress shows why some children are able to bounce back from trauma and abuse, while others suffer with depression and mental problems throughout their lives.
Adults who had been abused but didn't have the shielding variations in the gene had twice the symptoms of moderate to severe depression, compared to those with the protective variants, the Daily Telegraph reported.
The study gives evidence that a combination of gene variations and life experiences promote the disorder or protect people from it. Two-thirds of people are thought to lack the protective genes, doubling their risk of depression if they suffer childhood stress.
Dr Ressler said a test based on this understanding could appear ''in the not-too-distant future, no sooner than a decade I would say."