The Trauma Hijack

We've all heard of the fight or flight response. What's not as well known is the freeze response that's also a potential automatic response to danger. This is particularly relevant in the #metoo era to help understand people's seemingly unusual reactions during traumatic events.

The Neurobiology of the Stress Response

The amygdala is part of the caveman brain that handles threats. It responds to a threatening situation by stimulating the sympathetic nervous system, which drives the fight/flight/freeze response. It does this by triggering a different part of the brain, the hypothalamus. This then activates the pituitary and adrenal glands to release a flood of hormones. Those that are particularly relevant are cortisol, norepinephrine, oxytocin, and endogenous opioids (which are naturally produced in the body, such as endorphins).

Our brain doesn't want us busy thinking instead of reacting in a crisis, so norepinephrine turns down the volume in the prefrontal cortex, suppressing logical, rational thought and other advanced mental controls. The prefrontal cortex is normally the decision-making control centre of the brain, but since thinking can get in the way of survival, the primitive part of the brain takes over.

The brain also doesn't want pain slowing down the body's ability to react, and that's where the natural opioids come in. Not only do they blunt the pain, though, they can cause people to appear unemotional. This effect can persist for a few days, and it may appear to others that they're not having a "normal" reaction to the trauma they're reporting.

Oxytocin, another part of the chemical mix, can also have odd effects on people's post-trauma reactions, including making them laugh inappropriately. While this will likely strike observers as bizarre, it's not something that the individual has any control over.

Another part of the brain's trauma hijack is tonic immobility, also known as the freeze response. This involves a temporary, involuntary paralysis of the muscles. It occurs without any loss of consciousness, and is the result of combined actions of the sympathetic and parasympathetic nervous system and the adrenal stress hormone cortisol. This is not an uncommon response; some sources indicate that it happens in 50-85 percent of sexual assault victims.

Memory can also get muddled, and this is known as critical incident amnesia. Memories of the traumatic event often aren't accessible until two nights of sleep later.

What does this mean?

Society has all kinds of expectations how people "should" react both during and after traumatic events. If someone doesn't react in the way that's expected, the validity of their trauma might be questioned or they may be accused of not telling the truth. This type of mindset assumes that reactions to trauma are under conscious control.

The reality, though, is that our primitive caveman brain has been around far, far longer than any of these societal assumptions. The primitive brain, including the amygdala, aren't interested in giving people the opportunity to think and reflect on possible choices of actions. It is only interested in survival, and any parts of the brain that might interfere with that get temporarily shut down.

In a Canadian court case, a sexual assault victim was asked by the judge why she didn't simply keep her legs together to prevent her assaulter from penetrating her. This is ignorant on many levels, but it completely fails to take into account the tonic immobility that's part of the automatic freeze response. This woman likely wouldn't have had the motor control to close her legs, but even if she had, the higher level areas of her brain that might have been able to choose to do that were shut down by the biochemical processes associated with the freeze response.

People need to be educated on this, particularly those involved in the justice system that are dealing with victims of violence. No one's trauma should ever be judged on other people's arbitrary shoulds.