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Sustaining Stress and Trauma in the Body

The parasympathetic “slow-down” chemicals that numb us or make us “shut down” under stress play important roles in keeping our memory of intense experiences locked in the unconscious amygdala.  If that happens, the stored memory can be triggered later and come back as intense feelings, images, and sounds, as if it is all happening now (as it does in flashbacks).  This is because:

  • The chemical rush (particularly cortisol and endorphins) has shut down the process of recording conscious memory in the hippocampus.
  • Norepinephrine has stepped up the amygdala’s recording of unconscious memory fragments (van der Kolk and Fisler, 1995).

Each time these emotional memory fragments are triggered and reexperienced, we can actually be retraumatized by the memories themselves, even if there is no real threat in the present (Scaer et al., 2008).  And the chemicals that carry these signals tend to travel over the same neural pathways in the brain, over and over.  This makes it easier for signals of alarm to travel those pathways in the future, through a learning process called long-term potentiation.

In situations in which we are trapped or helpless, the parasympathetic arm of the stress system can send out chemicals (e.g., GABA, acetylcholine) that create a “freeze response.”  It does this largely through the work of the vagus nerve, a structure deep in the brain stem.  The heart rate slows, blood pressure drops, breathing becomes slow and shallow, and energy declines.  At the same time, though, all the sympathetic “fight or flight” chemicals are still pumping, so our intense experiences can be stored in our body’s procedural memory system (Scaer, 2005).

View a Summary of Increased Vulnerability

This is the same freeze state that animals in the wild enter when their predators are upon them.  From a primitive survival standpoint, the freeze is a reasonable response to helplessness, perhaps the most important part of the animal’s survival system (Levine, 1997).  In nature, the freeze takes place just before or at the moment the predator catches up with the prey.  “The stone-still animal is not pretending to be dead.  It has instinctively entered an altered state of consciousness shared by all mammals when death appears imminent” (Levine, 1997, pp. 15-16).  In a more familiar realm, it is the tendency of a bird to lie still and apparently stunned after banging into a closed window.

Animals in the wild follow this freeze response with a spontaneous discharge of the energy from these chemicals, often in the form of a rapid shaking or twitching motion.  The bird that lies still after crashing into the window eventually starts to shake, then flies away.  Animals who go through this discharge process actually become more resilient, while those not allowed to complete the discharge become weaker and more vulnerable (Levine, 1997;  Scaer, 2001).

Like other animals in captivity, human beings have lost the art of discharging the freeze response.  According to Levine (1997), our traumatic symptoms “stem from the frozen residue of energy that has not been resolved and discharged;  this residue remains trapped in the nervous system where it can wreak havoc on our bodies and spirits” (p. 19).  According to Levine, “The physiological evidence clearly shows that the ability to go into and come out of this natural response is the key to avoiding the debilitating effects of trauma.  It is a gift to us from the wild” (p. 17). 


The material on all of the Clinical Pages is taken directly from the draft version of Finding Balance After the War Zone:  Considerations in the Treatment of Post-Deployment Stress Effects, a manual under development for the Great Lakes Addiction Technology Transfer Center and Human Priorities.  This draft is copyright © 2008, Pamela Woll.  Reprint permission is universally granted, but attribution is requested.
Click here for References and Other Resources.
Click here to link to a PDF file of the current version of the clinician’s manual draft.
Click here to link to a PDF file of the accompanying booklet for veterans.

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