Children can inherit over-active brain circuits which link three parts of the brain, making them more prone to anxiety and depressive disorders, according to scientists.
To make their findings published in the journal `Proceedings of the National Academy of Sciences`, experts studying almost 600 young rhesus monkeys – which are the cousins of humans - from a large multi-generational family.
They found that around 35 per cent of variation in anxiety-like tendencies is explained by family history.
To understand which areas of the brain are responsible for passing on anxiety, scientists confronted the young monkeys with a stranger who did not make eye contact – the type of mildly threatening situation that a human child might also face.
During this encounter, researchers used brain imaging to measure behaviour related to anxiety.
The authors of the study were able to use this data to pinpoint the brain systems which are responsible for transmitting anxiety from a parent to a child.
Scientists found that three regions of the brain located in the brain stem were linked to hereditary mental illness: the amygdala, the limbic brain fear centre; and the prefrontal cortex, which humans use for higher-level reasoning.
Senior author Ned Kalin, chair of psychiatry at the UW School of Medicine and Public Health said in a statement: “Over-activity of these three brain regions are inherited brain alterations that are directly linked to the later life risk to develop anxiety and depression.
"Basically, we think that to a certain extent, anxiety can provide an evolutionary advantage because it helps an individual recognize and avoid danger, but when the circuits are over-active, it becomes a problem and can result in anxiety and depressive disorders," Kalin explains.
"This is a big step in understanding the neural underpinnings of inherited anxiety and begins to give us more selective targets for treatment."
