Trauma and the Human Brain: What happens in the wake of a disaster?

Why can’t I think straight?

Los Angeles experienced an unprecedented windstorm and fire event in January of 2025 that left thousands of people homeless and bereft. While the actual loss of life was relatively low given the seriousness of this disaster, the psychological toll on LA’s residents has been high. Many people report being unable to sleep or not being able to think clearly, and they also report reactivity to minor irritations.  

The post-disaster impact on residents is not unlike what happened to people post Hurricane Katrina and other natural disasters. When a person experiences an existential threat, their body does what it is designed to do and it kicks into a protective state. Their sympathetic nervous system shuts down all non-essential bodily functions and puts the body into survival mode. The fear response leads to a fight/flight/freeze reaction. The fear circuitry of the brain and nervous system by-passes the pre-frontal cortex (responsible for rational thinking, planning, remembering), and there is an increase in stress hormones as the body. The high alert state slows digestion, sex drive, and all other non-essential functions as the nervous system pushes the person toward the safest state possible. It’s important to recognize that it might take a while for a person to regain a sense of safety, even if the immediate threat passes.

Most of us have heard about the fight or flight response to trauma, but the freeze reaction is very common. With extreme trauma, an individual can experience tonic immobility – think possum effect – and might go limp or feel sleepy, maybe unable to speak or move, and it’s important to know that this is hard-wired into our systems. Dissociation is common. It’s a survival reflex, and what that means is that the person experiencing trauma will act in a habitual way but with very little control or knowledge of what they are doing. Additionally, because memory is not encoded in the brain sequentially, people who experience trauma may not be able to remember details of the traumatic event sequentially, and because their hippocampus is under-active, they will experience gaps in their memory of the event.  So, if you or someone you know feels like they can’t think straight, there’s a biological reason why this is occurring.

Getting people to safety and caring for their basic needs is a vital first step in dealing with trauma. Under normal conditions, as circumstances begin to feel safer, the parasympathetic nervous system activates and the body returns to a normal state over time. There are many types of practices that can help calm the nervous system and encourage down-regulation (prayer being one of them!) Studies indicate that most people do not experience PTSD (post-traumatic stress disorder) after a traumatic event. In fact, people are remarkably resilient and look to relational support, their religious beliefs, and other sources of meaning to make sense of their feelings about their experiences. For those who do experience an extended state of high alert, excessive irritability, flash backs, etc…professional help is often necessary, but for the majority of people experiencing natural disasters, their symptoms tend to dissipate within a 3-year period.  

What can you do to help yourself and others recover and bounce back?

1. Community support matters.  Just being present and experiencing the love of others can help our systems calm down and regulate. Twenty second hugs help activate the parasympathetic nervous system, so ask someone if they could use a hug and spread the love.
2. We can self-soothe with grounding and breathing practices.
3. We can grieve together and lament.
4. We can turn to our spiritual practices. 

If you want to learn more:

Listen to Drs. Jamie Aten and Pam King discuss research and strategies for recovering from trauma. 

Explore resources for recovering from disaster.

References

Eamin Z Heanoy, Norman R Brown (Editor: Alessandro Musetti ), Impact of Natural Disasters on Mental Health: Evidence and Implications, 2024.

How Trauma Affects the Brain

Neurobiology of Trauma