To understand PTSD, it is necessary to know a little about the workings of the brain. The brain is the seat of our thinking (consciousness/intellect) and feelings (instincts/impulses). The fact that we have a consciousness capable of thinking and understanding things is unique to us humans compared to other animals, but we share the part of the brain that is the seat of our instincts and feelings – also known as the reptilian brain or brain stem – with animals. The reptilian brain ensures our survival and tells us when something is nice, and when something is unpleasant – or perhaps even threatening enough to require fight or flight.
What characterises a traumatic experience is that a person feels in mortal danger and that there is nothing they can do about it. Thus, the crucial part is not whether the person actually is in mortal danger, or whether they really can get away, but how they perceive the incident at the moment it occurs.
Threats to your life are a matter of survival, so the alarm sounds directly in our reptilian brain. There is no time for when someone has PTSD? rational considerations when someone only has a few seconds to act. The alarm releases large amounts of energy, including stress hormones. Stress hormones prepare the body to be able to run fast, if it needs to flee, or to hit hard if it needs to fight the enemy.
As humans, we were highly dependent on this activation of energy when our forefathers lived as hunters and had to hunt to ensure survival, or combat threats that could destroy us. Wild animals constantly live by these instincts. Animals usually expend this energy through fight or flight – i.e. through violent physical activity.
If there is no possibility of fight or flight, the nervous system has a third survival strategy: “playing dead” or “freezing the body". The hunted animal goes into a kind of paralysis and becomes rigid. The internal driving force – hormone production – continues, but the brakes hold back the reaction. Not until the moment a way out is seen is the storedup energy released from the nervous system, and the animal has extra strength to make its escape.