By understanding the types of events that can trigger PTSD, you’ll be better equipped for your healing journey.

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Post-traumatic stress disorder (PTSD) is a condition that can occur after a distressing event.

In the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), the disorder falls under the “Other Trauma and Stressor Related Disorder family” to distinguish it from other anxiety disorders.

If you live with PTSD, your symptoms may include disturbing thoughts and feelings relating to the trauma, as well as nightmares, hyperarousal, flashbacks, anger, and memory issues.

If this sounds like you, you’re not alone. PTSD is one of the most common psychiatric disorders, impacting about 8 million U.S. adults.

By understanding the types of events that can trigger PTSD, as well as how it develops in your brain, you’ll be better equipped for your healing journey.

PTSD can be triggered by several distressing events. In essence, it can happen if you feel:

  • intense horror
  • helplessness
  • fear of a loss of life

It may occur more commonly than you realize. For example, of the 50 million people who experience road-related trauma every year, more than 22% in auto accidents develop PTSD.

Research suggests that those who’ve experienced interpersonal crimes, such as rape or being held at gunpoint, tend to have greater rates of PTSD than those who’ve had noninterpersonal traumas, such as natural disasters.

Common causes of PTSD include:

  • being the victim of a crime
  • childbirth experiences, such as losing a baby
  • childhood or domestic abuse
  • homicide of a loved one
  • mass violence, such as a mall shooting
  • natural disaster
  • physical violence
  • serious medical events, like being in intensive care
  • severe accidents
  • sexual assault
  • torture
  • war or combat

The nature of war puts many people at risk for PTSD.

According to the U.S. Department of Veterans Affairs:

  • 11% to 20% of Operation Iraqi Freedom and Operation Enduring Freedom (Global War on Terrorism) veterans developed PTSD in a given year.
  • 12% of Gulf War veterans developed PTSD within 1 year.
  • 30% of Vietnam War veterans are estimated to have had PTSD in their lifetime.

Other factors can contribute to PTSD and other mental health conditions in veterans. These include:

  • where the war is fought
  • the type of enemy you’re fighting
  • what you do in the war
  • the politics regarding the war

In a 2006 study, researchers found that 53% of prisoners of war (POW) met the criteria for lifetime PTSD. Those who had been stationed in brutal camps had higher rates of lifetime PTSD, hovering around 84%.

All 262 participants had either been POWs in World War II or the Korean War, and they had been exposed to multiple forms of trauma, including combat, capture, and imprisonment.

People of any age, gender, and background can experience PTSD, although it is more common in certain groups.

In the United States, research suggests that Black people, Latinos, and Native Americans have higher rates of PTSD than non-Latino whites. Women are also twice as likely as men to develop PTSD.

Evidence shows that women are more likely to experience childhood sexual abuse and sexual assault. Men are more likely to experience physical violence, accidents, combat, disaster, or be a witness to death or injury.

Other risk factors of PTSD include:

  • being a refugee
  • genetics
  • having extra stress on top of the trauma, such as poverty, homelessness, or grief
  • low level of support from family or friends
  • physical injury or pain during the traumatic event
  • previous depression or anxiety
  • repeated trauma
  • spending time in foster care
  • working in a high-risk job, such as in the military or a police officer

Being exposed to a traumatic event can lead to lasting changes in brain regions linked to stress, the most pronounced being the amygdala, hippocampus, and prefrontal cortex.

Fight, flight, or freeze

When a traumatic event occurs, your body releases large amounts of the stress hormones cortisol, epinephrine (adrenaline), and norepinephrine (noradrenaline).

This is known as a state of “fight-or-flight” response, your body’s way of preparing you for an attack while simultaneously dulling your senses and any potential pain.

Researchers now know that “freeze” is another possible response.

How the body “gets stuck”

For the majority of people, severe stress reactions are temporary. But for many, traumatic situations can lead to extreme mental distress and illness, including PTSD.

An estimated 50% to 60% of the general public has experienced at least one traumatic event, but only about 8% develop PTSD.

For those living with PTSD, the body gets “stuck” in a fight, flight, or freeze mode. Your body continues to release large amounts of stress hormones, especially when you encounter new stressors.

Physiological changes

The PTSD brain develops an overstimulated amygdala, responsible for identifying threats and infusing memories with emotion. A hyperactive amygdala sees threats everywhere.

PTSD may also lead to a smaller hippocampus, the part of the brain that regulates stress hormones and plays a major role in memory and learning, as well as fear learning and conditioning.

During PTSD, your hippocampus cells are destroyed by an increase in glucocorticoids (stress hormones). This makes the hippocampus less effective at its job of keeping your fearful memories in check.

This causes your brain to keep replaying fearful memories rather than processing that the traumatic event is over. This fear-based mechanism may play a role in the continuous nature of your flashbacks and nightmares.

Genetics appears to play a significant role in PTSD.

In a large genetic study of more than 200,000 people (and 30,000 people living with PTSD), researchers found that genetics accounts for 5% to 20% of PTSD risk following a traumatic event.

The researchers also found that similar to other mental health disorders, PTSD is highly polygenic. This means that it is associated with thousands of genetic variants, each making a small contribution to the condition.

A total of six gene regions, known as “loci,” were significantly linked to PTSD risk. Three of these loci were specific to ancestral heritage: Two were European, and one was African.

The 6 loci also suggest that inflammatory and immune mechanisms may play a role in PTSD, consistent with previous research.

The findings suggest that PTSD has just as strong of a genetic component as major depression and other mental health conditions.

Also, researchers found significant genetic overlap between PTSD symptoms of other conditions, such as schizophrenia, depression, asthma, insomnia, and heart disease.

If you’re living with PTSD, you’re not alone, and help is available. PTSD can be controlled and the symptoms essentially alleviated with therapy and medication. Regardless of your genetics or “clinical presentation” (how it manifests for you), there’s always hope.

Research has come a long way in identifying the causes of PTSD. This awareness has led to the development of very effective trauma-focused treatments.

The most evidence-based therapies for PTSD include:

You can begin your journey with our find a therapist tool. You may find it helpful to work with someone who has experience treating PTSD.