We’ve known for a long time that childhood abuse can leave long term damage and profoundly impact the life of an abused individual on into their old age. If you glance at any abnormal psychology textbook, and you look at suspected ideas of what causes personality disorders, childhood abuse is always on the list.
However, understanding what changes are actually taking place in the brain as a result of abuse have only really come to light over the last few years. This is mainly due to the bold and daring work of a number of neuroscientists – people like Dr. Eamon McCrory at the University College London.
Using fMRI, McCrory and his team found that children who had been exposed to family violence showed the same brain activity as combat soldiers, when exposed to an exercise where they viewed pictures of angry faces. If you just stop to think about that for a few seconds, it’s really very unsettling. The two brain areas that showed heightened activity in both abused children and soldiers were the amygdala (involved in fear recognition and memory formation), and the anterior insula (involved in emotion and self-recognition). McCrory suggested that perpetual exposure to negative stimuli, such as being subject to continued abuse or having to survive in a war zone, actually causes the hypersensitization of these two areas in the brain.
Hypersensitization means that those areas have essentially been trained to respond with a lot of activity, which over time means that there will be a large response, even when the stimulus is not as threatening or negative as the original (the abuse / the war zone). When the various parts of the brain have been calibrated to respond this way, the individual is likely to suffer from an anxiety or a stress disorder, or perhaps in the case of childhood abuse, a long term personality disorder.
A key difference, with regards to brain activity, between abused children and combat soldiers, is that the brain of the child is still developing. Brain maturation is complete at about the age of 25, but there are some crucial developmental stages during childhood. After the child is born to the age of 6, very important areas in reasoning and emotion are still growing and developing. So if a child experiences extreme stress, certain areas of the brain that have not matured yet will still respond to the environment, only the over activity and the stress could cause neurochemical changes that stymie neuronal growth, meaning that these areas will never develop correctly.
When this happens the child could end up with a personality disorder – the worst case scenario being antisocial personality disorder, or psychopathy.