Can You Inherit Stress?

Our busy lives have become increasingly stressful, and each of us has a different idea of what stress is and means. But the really important factor is how we handle the stressors we are inevitably confronted with. Some people seem able to calmly take all that life throws at them, while others react badly to the slightest upset. 

Do we learn to cope with stressful situations — in the same way that we learn other life skills — or is our ability to deal with stress shaped by our childhood experiences?

This is a very complex issue and there is much controversy and research in this area. But it appears that there is more than one way in which our parents could influence our ability to handle stress.

Biological response to stress

When we respond to stress, our bodies prepare for action – known as the ‘fight or flight’ response – mostly mediated by hormones.  This ‘programming’ developed early in our evolution as it was a life-saver that helped us avoid danger and stay alive longer to reproduce (which is what life was all about in those days!).  

But those who were too laid back to bother running away from the hairy mammoth, would not survive long enough to pass on their genes!

Early indicators of response to stress

Nowadays, our response to stress is not so critical to survival and researchers have shown that babies vary in how reactive they are to stress.  A normal response to stress is that our heart rate speeds up, which is due to a reduction in the slowing influence of the vagus nerve, on the heart. (When preparing for fight or flight you need your heart to be pumping blood vigorously round your body - to your muscles, lungs and brain, so you can run or battle).

Cathi Propper, a developmental psychologist at the University of North Carolina at Chapel Hill, and her colleagues, studied children during their first year of life. They stressed the babies by taking them away from their mothers, and measured their heart response. 

These low responders had a variant of a gene which has been associated with risk-taking behavior in adults, such as gambling.  But interestingly, this was not the final determinant of the children’s behavior.  It was found that the response of these children normalized over time if they were cared for by sensitive, attentive parents. In other words, nurture won out over nature – the children’s upbringing became more important than their inherited genes.

Handling Stress And Other Hereditary Factors

Another inherited trait which appears to be of significance in handling stress is the ability to produce a substance called neuropeptide Y (NPY). This substance, secreted by the brain, helps us to calm down after stressful events. Researchers at the University of Michigan have found that some people inherit genes which mean they only produce low levels of NPY. 

This can make these people more likely to also suffer from depression in response to stressors.

Differences in brain response

Modern technology enables researchers like Professor Guillen, of the Donders Institute for Brain, Cognition and Behavior in Nijmwegen, in the Netherlands, to monitor the response of key areas of the brain when people are subjected to stress. He has studied activity in an area of the brain called the amygdala, which is associated with processing emotions. It has been found that there is a gene which determines how stressed out an individual becomes. Prof. Guillen said:

'This individual genetic difference only surfaces when people are subjected to stress. This is the first time a genetic variation has been found that shows a different response to emotional stimuli only when individuals are stressed.'

He is also investigating whether this gene affects how likely people are to suffer from post-traumatic stress disorder after a traumatic event, as this response can be very variable from one individual to the next.

Early experiences are influential in stress response

If mouse research translates into the same effects in humans, it could highlight how important it is to protect children from stressful challenges early in life. Laboratory mice were subjected to social stress when they were young, by being constantly moved between cages. When given tests as adults, it was found that the female mice exhibited anxiety, but the males did not. But both sexes passed on anxiety behaviors to their offspring. 

Is it all down to genes then?

No. While genetics clearly have a big impact, as children we are very influenced by our parents’ behavior as well as the social norms of the community around us. So if our parents easily become stressed and handle challenges badly, we will often develop in the same way and tend to copy their behavior.  But the good news is that because that is a learned behavior, we can learn how to control it and modify our response to stress.

Like a lot of good ideas, that’s probably easier said than done!