How Does PTSD Affect the Brain? Exploring the Neurological Impact of Trauma

Post-traumatic stress disorder, PTSD, affects the brain on a neurological level and can interfere with regular brain function. Understanding these impacts can help you better appreciate the long-term effects of untreated PTSD and why it’s important to get help.

PTSD And the Brain


PTSD results from exposure to severe trauma. You don’t have to have experienced a traumatic incident personally to struggle with PTSD; it could be something that happens to a loved one or something that you witness. This article will explore the way PTSD affects the brain and its neurotransmitters and why it’s important to seek treatment.

PTSD symptoms are divided into three categories:

  1. Reminders: This includes flashbacks, nightmares, and intrusive thoughts.
  2. Activation: this includes hypervigilance, hyperarousal, anger, agitation, irritability, insomnia, and impulsivity. 
  3. Deactivation: this includes avoidance, dissociation, depression, withdrawal, confusion, and numbing. 

PTSD is characterized as having symptoms from all of these categories for more than one month after exposure to a traumatic event. Symptoms of PTSD can interfere with daily life causing you to avoid situations, environments, or people who might remind you of the traumatic event and cause flashbacks. Nightmares can lead to increased insomnia. You might experience hypervigilance or hyperarousal, where your body remains in a fight-or-flight state, and you are constantly looking for potential threats.

The neurobiology of PTSD

So why does all of this happen? It has to do with PTSD’s effects on the brain. What does PTSD do to the brain?

All the areas of your brain work together. Your brain regularly looks for threats, real or perceived. This is an essential function for survival. Historically it allowed the human species to scan a horizon and determine whether the dark outline was a rock or a lion. The brain’s limbic system filters this information and causes you to freeze, fight, or flee.

The amygdala is in the center of the brain, and it’s the fear center. If there is a perceived threat, the amygdala tells the hypothalamus, which is responsible for regulating mood, sleep, and hunger, to release stress hormones like cortisol. The amygdala also triggers the sympathetic nervous system so that you can freeze, fight, or flee. 

PTSD changes the brain so that the amygdala triggers this response when it shouldn’t, and this causes impulsivity, agitation, sleep disturbances, and poor decision-making. It also physically changes the size and structure of different parts of the brain. Where the prefrontal cortex might be responsible for controlling impulses, that area of the brain can begin to shrink, allowing for other areas of the brain that control impulsivity to increase.

What Does PTSD Do to the Brain

Neurotransmitters and PTSD

Many PTSD effects on the brain can severely impact your daily function. Neurotransmitters in the brain normally work to control:

  • Emotions
  • Aggression
  • Impulsivity
  • Stress
  • Memory
  • And more

When PTSD changes the brain, it starts by influencing your neurotransmitters, leading to mood imbalances, increased anxiety, and hyperarousal.

Serotonin is often decreased in individuals struggling with untreated PTSD, and this can lead to hypervigilance, where you are constantly looking for the next threat and are unable to bring your resting adrenaline rate back down to normal. This has many long-term implications and can lead to severe damage. 

Decreased serotonin transmissions result in increased anxiety levels. It also means you are more likely to be impulsive and struggle with increased aggression.

Similarly, noradrenaline (NA) is responsible for mediating your stress response, but with PTSD, you end up having increased noradrenaline which directly influences the hypothalamus in the amygdala, increases your fear, and starts to code new and old emotional memories with increased arousal and hypervigilance.

Structural and functional changes in the Brain & HPA Axis Dysregulation

How does PTSD affect the brain? PTSD and the brain are not meant to work together, especially where neuroendocrine functions are involved. The hypothalamic-pituitary-adrenal (HPA) axis controls how you respond to stress. This is where your stress response begins.

In the HPA axis, a hormone called CRH is released. CRH is reasonable for stimulating ACTH from your anterior pituitary gland. When this happens, it stimulates cortisol. High cortisol levels result from any form of high stress, including chronic stress.

High cortisol levels can inhibit the HPA axis and lead to HPA axis dysregulation. PTSD changes the brain by reducing the size of your hippocampus. This negatively impacts your ability to store memories and regulate emotions.

Long-term effects of PTSD on the brain

Long-term effects of PTSD on the brain take many forms. 

Cognitive Decline

With increased noradrenaline levels and increased hypervigilance in arousal coded to emotional memories, you are more likely to have high resting adrenaline rates, feel anxious, on edge, and depressed because so many of the new memories you are trying to store are connected with negative emotions.

For example: A client gets attacked in a grocery store parking lot. A man pushed her into her car, knocked her to the ground, and proceeded to yell at her, degrade her, kick her, and punch her. 

Each time she thinks about needing to go to the store or needing to buy something, she starts to struggle with hypervigilance, anxiety, and negative emotions. Every visit to the store gets coded with more negative emotions. 

Every potential volunteer request or school activity that requires her to go to that same store or visit a similar parking lot gets coded with negative emotions. Over time this increases her anxiety and hypervigilance, leading to irritability, anger, and chronic stress levels.

In this example, the client is more likely to struggle with cognitive decline as a direct result of neurobiological changes and high resting cortisol levels.

Psychiatric Disorders

Untreated, long-term effects of PTSD on the brain can lead to psychiatric disorders. Individuals who are hypervigilant, struggling with intrusive thoughts and flashbacks, and dissociation are more likely to suffer from psychosis, major depressive disorders, and anxiety disorders.

Physical Health Problems

PTSD changes the brain for the worst, and if left untreated, it can cause physical health problems. Many people with PTSD self-medicate, turning to drugs and alcohol, which leads to co-occurring substance abuse disorders. Even without a substance abuse disorder, there are high risks that the impact of PTSD and the brain will lead to issues such as:

  • High blood pressure 
  • Fatigue
  • Joint pain
  • Back pain
  • Headaches
  • Muscle tension
  • Nausea
  • Heart disease
  • Gastritis
  • Arthritis
  • Physical function
  • Stomach ulcers
How Does PTSD Affect the Brain

Summing up

Early intervention is essential. Anyone questioning what PTSD does to the brain should consider getting professional intervention and treatment as early as possible to mitigate the long-term effects of PTSD on the brain.

Several evidence-based treatments and therapies can be used to help overcome symptoms of PTSD. The World Health Organization and the Department of Veterans Affairs both rely on EMDR as their primary evidence-based treatment for PTSD. Other options include cognitive behavioral therapy, trauma-informed approaches, and incorporating self-care practices and lifestyle factors to boost your brain health. If you are struggling with symptoms of PTSD, don’t wait for PTSD effects on the brain to become a serious problem. Get professional help, promote your brain health, and foster resilience today.