The Human Autonomic Nervous System and Emotional Flashbacks

CPTSD Foundation
6 min readJan 18, 2021

Emotional flashbacks are troubling and often disabling events that cause a person to experience alarming and crippling bursts of strong emotions. Emotional flashbacks are experienced without the linked visions from the past that accompany average flashbacks.

In this article, we shall examine together what is going on in the autonomic nervous system (ANS) of those experiencing emotional flashbacks.

What is Trauma?

Trauma is a normal response to abnormal situations such as a car accident or other life-altering event. The best definition I have ever read for trauma is a quote by Cody Wiggs, LPC and it states:

“Trauma is an event, or series of events, which overwhelms the central nervous system. Trauma occurs when one’s ability to defend, protect, or say no is overwhelmed.”

However, the type of trauma that is the cause for emotional flashbacks involves complex trauma which both describes a child’s exposure to repeated traumatic events and the long-term effects of this exposure.

Complex trauma includes all forms of child abuse, adverse childhood experiences (ACEs), domestic and family violence, war, sexual exploitation, and human trafficking.

Complex trauma trains the child’s limbic system, the amygdala, sympathetic, and sympathetic nervous systems, to be constantly on the alert for approaching danger.

The Hijacked Amygdala

To understand emotional flashbacks, we must first discuss the amygdala. The amygdala is a collection of nerve cells located near the base of the brain and considered part of the brain’s limbic system. There are two parts to the amygdala, one on each side, and it is vital for humans to recognize and respond quickly to danger.

The amygdala is one of the most primitive parts of our brain, continuously collecting data from our five senses and on the lookout for dangerous situations where it must act. When the amygdala senses danger, real or imagined, it secrets a series of hormones that signal the fight/flight/freeze response to occur.

After the secretion of these hormones, the body begins to rev up reacting quickly to the real or perceived danger to decide, without thinking about it first, how to react.

Trauma disrupts the amygdala’s ability to work properly. In many cases, trauma leads to a hijacking of this tiny organ causing it to misfire, when triggered, and respond inappropriately when there is no danger.

The trigger for the amygdala to respond might be a sound, sight, smell, or texture that reminds the person experiencing an emotional flashback of the trauma they endured weeks or even years after the event.

The Sympathetic and Parasympathetic Nervous Systems and Emotional Flashbacks

Emotional flashbacks are experienced without sounds, sights, or smells but instead are emotions that are inappropriate and out of proportion to a trigger. This psychological reaction is not coming from events in the present but instead from events from the person’s past. Usually, the person experiencing the emotional flashback doesn’t know what the triggering event is that sends them spiraling into an emotional tailspin with feelings that run the gambit from fear to intense feelings of abandonment.

These sudden bursts of intense emotions unleash a monstrous response from our amygdalae stimulating our autotomic nervous systems to action. The result is an intense outburst of our fight/flight and freeze responses.

The autonomic nervous system (ANS) is in charge of our most basic automatic functions like heart rate, hormone regulation, breathing, and our body’s response to stressful events. Divided within the ANS are the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).

The work of the sympathetic nervous system (SNS) revs up the body via secreted hormones for the fight/flight/freeze response while the parasympathetic nervous system (PNS) calms us down once the danger has passed.

If a child is exposed to the repeated triggering of their autonomic nervous system as in the case of repeated child abuse, their SNS becomes constantly triggered as the amygdala sees danger everywhere and the child’s PNS becomes much weaker in its ability to return the child to a baseline of calmness. These interruptions in function leave the child in a constant state of alertness.

As adults, these effects leave long-lasting scars as a trigger can cause a cascade of events to occur in their bodies and brains paralyzing the survivor in their inability not to react to triggers that are not real.

Bringing it All Together

We have only skimmed the surface as to the different parts of the body and brain that are involved in the formation of a mental flashback. There are literally hundreds of different moving parts to not only the emotional flashback itself but also to the reactions toward the cascade of emotions felt as a result of having one.

Emotional flashbacks contain all the emotions but few if any of the memories of what happened to form them. One may feel the emotions of fear from being in a war zone as a child without any memories of what that child saw or experienced.

The amygdala and autonomic nervous systems are major players in the causation of an emotional flashback as they interact leaving the adult experiencing one struggling back to the hear and now from emotions that occurred perhaps decades before.

Our next and final article for this series will focus on the treatments that are used to treat emotional flashbacks and some grounding techniques to help pull yourself back to the now.

“After a traumatic experience, the human system of self-preservation seems to go onto permanent alert, as if the danger might return at any moment.” ~ Judith Lewis Herman

“Cry. Forgive. Learn. Move on. Let your tears water the seeds of your future happiness.” ~ Steve Maraboli


McCorry, L. K. (2007). Physiology of the autonomic nervous system. American journal of pharmaceutical education, 71(4).

Walker, P. (2009). Emotional flashback management in the treatment of Complex PTSD. Psychotherapy. net.

Wiggs, C. (2017). Mindfulness & Trauma Part 1 of 4: Defining Trauma. Retrieved from:

If you are a survivor or someone who loves a survivor and cannot find a therapist who treats complex post-traumatic stress disorder, please contact the CPTSD Foundation. We have a staff of volunteers who have been compiling a list of providers who treat CPTSD. They would be happy to give you more ideas about where to look for and find a therapist to help you. Go to the contact us page and send us a note stating you need help, and our staff will respond quickly to your request.

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Originally published at on January 18, 2021.



CPTSD Foundation

Successfully equipping complex trauma survivors and practitioners with compassionate support, skills, and trauma-informed education since 2014.