We have discussed this before and it is clearly a factor for many of us.

"...The brains of children are affected by family violence in the same way as combat affects soldiers, according to a study.

In both cases the brain becomes increasingly wary of potential threats.

.....

The scans suggest both combat veteran soldiers and children who witness violence tune their brains to be hyper-aware of environmental danger.

....

However, it may also constitute an underlying neurobiological risk factor increasing their vulnerability to later mental health problems, and particularly anxiety."

Read more: http://www.dailymail.co.uk/sciencete...#ixzz1fwj3OwEB