Survival Instinct and Post-Traumatic Stress Disorder

Understanding the Role of the Nervous System in Trauma

Throughout life, most people encounter difficult or potentially traumatic events. Research suggests that an individual may be exposed to several such events during their lifetime.

Understanding how our nervous system responds to danger can help shed light on certain emotional and physical reactions that sometimes persist long after an event has passed.

This article offers an overview of survival mechanisms and their relationship to trauma, inspired in particular by the work of Dr. Peter Levine, founder of Somatic Experiencing®.

What Is a Traumatic Event?

A traumatic event is generally defined as a situation that exposes a person, directly or indirectly, to:

• a threat of death
• serious injury
• sexual violence

Examples of events commonly associated with shock trauma may include:

• accidents
• serious falls or illnesses
• assaults
• natural disasters
• war or acts of terrorism
• certain losses or separations that can be deeply destabilizing

When traumatic experiences occur repeatedly during childhood, they are often referred to as developmental trauma.

Symptoms of Traumatic Stress and Post-Traumatic Stress Disorder

The effects of a traumatic event may appear immediately after the experience, but they can also emerge months or even years later.

When these reactions persist and significantly affect daily life, they may be associated with what is commonly known as post-traumatic stress disorder (PTSD).

Symptoms may manifest in different ways, for example:

• persistent anxiety
• sleep disturbances or insomnia
• panic attacks
• phobias
• psychosomatic pain
• agitation or hyperactivity
• a diffuse sense of insecurity or unease

These reactions may be related to a prolonged activation of the nervous system, as if the body continues to perceive a threat even when the danger has already passed.

Instinctive Survival Responses

When facing danger, the human body automatically activates biological responses designed to promote survival.

These instinctive responses are commonly described as:

• fight
• flight
• freeze

These reactions occur rapidly and automatically, largely independent of conscious thinking.

Similar survival strategies can also be observed in many wild animals.

The sympathetic nervous system prepares the body for action such as fight or flight, while parasympathetic pathways are involved in regulation and recovery.

Why Do Animals Rarely Develop Trauma?

In the wild, animals are constantly exposed to threats. Yet they rarely appear to develop long-term traumatic symptoms.

One observation is that their nervous system tends to return naturally to a state of balance once the danger has passed.

After escaping a predator, animals may tremble, shake, or release tension before returning to their normal activities. These reactions seem to support the natural regulation of the nervous system.

The Freeze Response

When fighting or fleeing is not possible, a third survival response may occur: the freeze response.

This state may involve:

• sudden immobility
• reduced breathing
• numbness or shutdown
• sometimes dissociation

Although it may appear as complete stillness, freeze actually involves a high level of energy mobilization in the nervous system. It can sometimes be compared to pressing the brake and the accelerator at the same time.

The Role of the Human Brain

According to Peter Levine, an important difference between humans and animals lies in the development of the neocortex, the part of the brain involved in perception, cognition, and social interaction.

This development allows human beings to reflect, anticipate consequences, and assign meaning to events. However, it may also interfere with instinctive nervous system responses during traumatic experiences.

The Somatic Experiencing® Approach

Somatic Experiencing® is a body-oriented therapeutic approach developed by Dr. Peter Levine.

It is based on several key ideas:

• the body has an innate capacity for self-regulation
• trauma is primarily expressed within the nervous system
• certain survival responses may remain incomplete after a difficult experience

This work unfolds gradually within a safe and supportive context, with the aim of supporting the regulation of the nervous system.

Further Reading

For those interested in learning more about Peter Levine’s work, his book Waking the Tiger presents the foundations of the Somatic Experiencing® approach.