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Factors that influence whether post-traumatic stress disorder will occur

PTSD is rarely caused by a single event or entity, so it is more appropriate to talk about ‘risk’ and ‘protective' factors rather than causes
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© University of Glasgow

The belief that post-traumatic stress disorder (PTSD) is simply ‘caused’ by a traumatic stressor is challenged by a large body of research highlighting a multitude of risk and protective factors that seem to influence whether or not PTSD occurs (Ford et al., 2015). In fact, the majority of individuals who experience a traumatic event do not develop PTSD.

The experience of a traumatic stressor is necessary but insufficient for the development of the disorder. As mental disorders such as PTSD are rarely caused by a single event or entity, it is more appropriate to talk about PTSD ‘risk factors’ and ‘protective factors’ rather than PTSD ‘causes’ per se.

This implies that the aetiology, or development, of PTSD is often co-determined by a complex set of factors, which can be biological, psychological and social in nature.

Risk and protective factors

One can distinguish between three broad groups of factors that can affect the likelihood, severity and trajectory of PTSD: pre-traumatic, peritraumatic and post-traumatic factors.

  • Pre-traumatic or pre-event factors occur before the traumatic event takes place and can lower or increase the risk of PTSD.
  • Peritraumatic factors exert their influence during or shortly after the event.
  • Lastly, post-traumatic factors occur after the event and play a key role in the trajectory of, and recovery from, the disorder.
Type of factor Examples
Pre-traumatic factors – Personal characteristics such as ethnicity, age, gender, personality, memory, learning style, motivation and genetic characteristics.
– Contextual characteristics such as access to socio-economic resources.
– History of psychiatric disorders and other medical history. Previous exposure to traumatic stressors.
Peritraumatic factors – Heightening physiological reactions such as increased blood pressure and exhaustion.
– Dissociation — for example, impaired memory as a result of an overwhelming emotional response to a stressor.
Post-traumatic factors – Social support
– Access to culturally-sensitive and evidence-based treatment options.
– Development of coping styles and self-efficacy.


Factors increasing the risk of PTSD

There is a complex web of risk and protective factors for treatment and prevention effectiveness in PTSD. Take time to reflect on observations you have made in relation to individuals who have experienced traumatic events.

It is helpful to be aware that the risk of PTSD is also increased if:

  • The traumatic stressor involves gross violations of one’s dignity, basic needs or security of attachment relationships. Examples include torture and sexual abuse in the family.
  • There is severe and long-lasting physical injury or other health complications.
  • There is a history of adverse childhood events.
  • There is a reluctance or inability to disclose.
  • The traumatic stressor is characterised by unpredictability, lack of control and suddenness.


Ford, J. D., Grasso, D. J., Elhai, J. D., & Courtois, C. A. (2015). Posttraumatic Stress Disorder: Scientific and Professional Dimensions. New York: Academic Press. doi: 10.1016/B978-0-12-374462-3.X0001-9

© University of Glasgow
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Post-Traumatic Stress Disorder (PTSD) in the Global Context

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