Both PTSD and traumatic stress in general, occur because of the way the human brain is designed, not because of an inherent weakness in the individual.
As we saw in module 3 (addiction neuroscience) the brain is divided into older and newer sections (the limbic brain and the cortex). These brain areas developed at different times in human evolution. The cortex tends to control rational thought processes (cognition) while the limbic brain controls emotions and gives us an overall ‘instinctive’ idea of how to respond to things. It also helps us to regulate our automatic body functions coming from the deepest part of the brain. Things such as heart rate, threat detection, aggression and escaping. The limbic system doesn’t need much input from the cortex to achieve this. It is quicker than the cortex and forms our first line of defense against incoming threats.
Fig. 1 The cortex (which controls rational thinking) is too slow in its processing ability to be of much use in an emergency situation and is often overruled by our ‘animal’ instincts
Two writers who have contributed greatly to our modern understanding of traumatic stress are the psychologist Peter Levine, and psychiatrist Besel Van der Kolk. Both of them have studied what is known as the body’s ‘fight-flight’ response. Fight-flight response is an automatic bodily reaction that occurs whenever we experience an emergency or life threatening situation (or what we ‘think’ is a life threatening situation). When this happens we don’t actually ‘think’ our way out of it. Our body takes over and we leap into action.
In his book ‘Waking the Tiger’ Levine explains how one of the things that prevents ongoing traumatic stress (even when something terrible has happened) is that the person is able to mount a successful fight or flight response. In other words, they managed to do something about it. Being able to successfully fight or flee helps greatly in overcoming the traumatic event. If fight or flight is successful, then our nervous system helps us to gradually regain our composure.2
However, if for some reason this instinctual response is blocked (for example, if we are trapped, or being held down) then we might ‘freeze’. During this freeze response the brain continues to secrete stress hormones and other distress signals long after the actual threat has passed. This is what causes trauma. People suffering from post-traumatic stress are stuck in a battle they feel they cannot win, and then become ingrained in pattern of trying to escape from a threat which is long gone.
- Fight – when we are in danger, if we believe that we can win then we instinctively ‘fight’ back without thinking about it
- Flight – If we instinctively know we are unlikely to win, then we run without being able to control it
- Freeze – If we instinctively feel we are likely to die, then we freeze to make our impending death less painful
The technical word for fight-flight is hyperarousal. And the technical term for ‘freeze’ is the immobility response.