Researchers have discovered that the effects of trauma can be passed genetically from parents to children. The insight was found while looking at the offspring of children who were displaced during World War II, revealing they were four times more likely than those whose parents were not displaced to suffer mental health issues.
In the largest investigation ever of its kind, researchers examined the health records of 3,000 children of Finnish people evacuated to Sweden during the 1941-45 conflict with Soviet Russia. The evacuees, many of whom were at a pre-school age, were placed with foster families in Sweden and were forced to learn Swedish, later returning to Sweden.
The researchers found that the effects were specific to female children displaced during the war, as the future children of boys were less affected.
The study found that the children of these girls had an increased risk of being hospitalised for conditions such as depression and bipolar disorder, however this was not replicated among children of boys displaced during the war.
Its authors say the effect may be partially explained by poor parenting by the evacuees, but they believe it is more probably due to epigenetic alterations - changes to the way genes are expressed - which are then inherited.
Though the policy of removing children from their homes during the war was intended to protect them, researchers believe the unintended consequences may be no less problematic.
"Our observation of long-term psychiatric risk that reached into the next generation is concerning and underscores the need to weigh benefits as well as potential risks when designing policies for child protection."