The Biology of Trauma

In her new book, The Biology of Trauma, Aimie Apigian MD* breaks the body's trauma response down in a way that I find useful. Specifically, she describes a five step process: 1. the startle (an inner state of hypervigilance in response to a potential danger), 2. the stress response (a high-activation state), 3. the wall (an inner state of powerlessness), 4. the freeze (an inner state of paralysis), and 5. the shutdown (an inner state of heaviness or numbness).

The startle describes the moment our nervous system detects a potential threat. The hypervigilance and alertness felt during this phase is due to a surge of the neurotransmitter #norepinephrine.  Specifically, when the area of the brain called the #amygdala receives input from external or internal sources suggesting danger, this reflexively triggers an increase in sympathetic nervous system #SNS activity (by way of the #hypothalamus and #brainstem). The same response is triggered regardless of whether the threat is physical (like abuse or a car accident), psychological (like self-defeating thoughts or inner criticism), or social (like rejection, loss, or exclusion). The norepinephrine provides a brief surge of energy and alertness to facilitate the threat assessment. Stephen Porges, an expert in autonomic nervous system functioning, describes this assessment process as “neuroception.” It involves a continuous monitoring of many inputs to constantly assess our capacity vs. demand in order to determine our level of danger and ultimately decide what mode of operating our nervous system should be in. The norepinephrine alerts that a new potential threat may impact the equation.

The five steps of the body's trauma response, as described by Aimie Apigian, MD in The Biology of Trauma

Once #neuroception decides you're in danger, the next step is the stress response, which results in a surge of high-intensity energy (by way of norepinephrine, #dopamine, #adrenaline and #cortisol release, among others) to either fight or flee. If the stress response is not enough to overcome or evade the (perceived) threat and neuroception deems that the danger is, or has become, greater than our capacity, our body proceeds to the next step. This might happen very quickly, or it may be prolonged. Regardless, Apigian describes "the wall" as the moment when our nervous system recognizes that we are trapped in the face of danger and unable to escape, and therefore it’s time to switch survival strategies. This moment triggers an overwhelming and unbearable inner experience of powerlessness, which is ultimately what launches the next steps of the #trauma response.

The next one, the freeze, is designed to limit the amount of energy we waste once fighting or fleeing has been deemed futile. An emergency brake is deployed and our muscles lock tightly, trapping all the energy from the stress response in our body. Both the sympathetic and parasympathetic nervous systems #PNS are engaged, and we feel frozen in paralysis, at least at first… But then comes the final step, the shutdown. When we hit this point, Apigian summarizes the survival strategy as “don’t die, but stay barely alive.” We power down to conserve energy. Doing so involves three #trauma survival mechanisms: dissociation, immobilization, and energy conservation.

As Apigian explains, #dissociation "cuts off our presence to protect us from emotional overwhelm." It's our body's way of protecting us from feeling more than we can handle - of creating mental distance when physical escape is impossible. It explains why memories of overwhelming events are often fragmented and hard to piece together. It’s also often how trauma survivors function in their everyday lives despite struggling internally. Their "just get shit done" mode operates even when their mind is elsewhere.

The immobilization survival mechanism is a whole body response and a distinct inner state that is familiarly awful to most trauma survivors. Apgarian notes that part of this awfulness stems from the fact that it contradicts our body's natural instinct to fight or flee in response to fear. But once neuroception has determined that stillness, not action, is best for survival, the parasympathetic nervous system's emergency brake overpowers any sympathetically-mediated fight or flight fuel (and certainly any input from conscious will). But immobilization doesn't just result in physical paralysis - emotions can also get stuck in our body and mind, and aspects of our experience can get frozen and fragmented. This is where parts work approaches (e.g., #IFS, #TIST) and #somatic approaches (e.g., #SE, #SP) can be helpful to reconnect with those stuck parts and the emotions and somatic memories they hold.

The last trauma survival mechanism can be the hardest to understand and accept - energy conservation. Apigian explains that it’s difficult for our rational mind to grasp why "not doing" or "giving up" is a useful response to danger, but once neuroception deems fighting futile, then preserving energy really does become the best option from an evolutionary standpoint - we produce less heat and move less and therefore become less detectable by predators. We also preserve what little energy we may have in case an opportunity for escape presents itself. 

But the effects of energy conservation on mind and body can be particularly unpleasant. As the body systems slow and start to malfunction from energy depletion you might feel cold and heavy, foggy or flat, and/or have difficulty with decision-making. You may be left with a disoriented or dazed feeling, as well as problems with digestion and temperature regulation. You might have a strong desire to curl up in the fetal position and never move again. Anything that takes energy can feel impossible. As Apigian notes, "you may find yourself simply following instructions without resistance, rather than wasting energy fighting back or trying to figure things out." 

This last survival mechanism is underappreciated by many trauma survivors, and I think this contributes to (undeserved) feelings of #shame. Survivors judge themselves for not fighting back, for staying with that asshole boyfriend, for being compliant, for letting it happen again. They neglect to consider the impact of their autonomic nervous system state when doing so. We like to think we're in control of what our body does at all times, but when you’re under threat, the nervous system is calling the shots. When you are in a trauma response, no amount of willpower can overcome biology. Starting to shed the shame and self-blame and truly understand that your body was doing its best to survive is often an important part of healing. Learning how the threat response works also provides useful clues on how to recover from past traumas and how to better navigate future ones.

*Note: This is not an endorsement of everything Aimie Apigian MD has to say, her courses, or even her book - I just find her description of the trauma response useful and clear.