The causes of post-traumatic stress disorder (PTSD) are not well known or understood. Posttraumatic stress disorder is an anxiety disorder that occurs after being involved in a traumatic event involving harm, or threats of harm, to the self or others. Even learning about an event has the possibility of causing PTSD in some people.
Prior to the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM) in 1980, PTSD was not recognized, and those who exhibited the symptoms were considered to be having an exaggerated stress reaction. This reaction was attributed to a character flaw or personal weakness. We now know that character does not cause PTSD and there are physical, genetic and other causes of PTSD at work. (Wondering "Do I Have PTSD?" Take our PTSD test.)
While one could think of the trauma as the cause of PTSD, some people can undergo a trauma and not develop post-traumatic stress disorder. Post-traumatic stress disorder is initiated by a trauma, but the causes of PTSD are related to the brain and risk factors for developing an anxiety disorder. (Even though the complete cause of PTSD is not known, PTSD help and effective treatments are available.)
The events most likely to cause post-traumatic stress disorder (PTSD) are:1
- Combat exposure
- Childhood neglect and physical abuse
- Sexual molestation
- Physical attack
- Being threatened with a weapon
However, any kind of event perceived as traumatic can trigger post-traumatic stress disorder (PTSD).
Physical Causes of Post-Traumatic Stress Disorder (PTSD)
Brain structures and brain chemicals have both been implicated in the causes of PTSD. Research shows that exposure to trauma can cause "fear conditioning" of the brain. Fear conditioning is where the person learns to predict traumas and the predicted traumas cause parts of the brain to activate. With post-traumatic stress disorder, fear conditioning causes the brain to anticipate danger where none exists, causing PTSD symptoms.2
Additionally, the parts of the brain that are designed to dampen this fear response seem less capable of doing so in those with PTSD. This may be caused by stress-induced atrophy of the brain structures in that area.
PTSD Causes: Risk Factors for PTSD
It's possible for two people to go through the same trauma and only one will develop PTSD, indicating that some people carry additional risk factors for post-traumatic stress disorder. Genetics is thought to pass down some of the physiological vulnerability that leads to the causes of PTSD.
Personal characteristics are also known to increase the risk for PTSD. Characteristics that can contribute to post-traumatic stress disorder (PTSD) causes include:
- Exposure to previous traumas, particularly as a child
- Childhood adversity
- Preexisting conditions like anxiety or depression
- Family history of anxiety or depressive disorders
- Gender (more women than men develop PTSD)
Some of the causes of PTSD are thought to be related to the type of trauma itself. Exposures that are more likely to cause PTSD are:
- More severe
- Longer in duration
- Closer to the individual
Some factors can predict a better outcome for PTSD. These predictive factors include:
- Availability of social support
- Lack of avoidance or emotional numbing symptoms
- Lack of hyperarousal (also known as the fight-or-flight response) symptoms
- Lack of symptoms related to re-experiencing the trauma