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Definition and history of PTSD

Definition and history of PTSD

This animation presents a short history of PTSD as a distinct clinical entity.

There are various definitions of PTSD available. For the purposes of this course, the definition presented in the International Statistical Classification of Disease and Related Health Problems Version 11 (ICD-11) is accepted and used. Take some time to read about the definition of PTSD according to ICD-11.

The International Statistical Classification of Disease and Related Health Problems Version 11 (ICD-11) was published in 2019 and conceptualises PTSD as a disorder that:

“may develop following exposure to an extremely threatening or horrific event or series of events. It is characterised by all of the following:
  • Re-experiencing the traumatic event or events in the present in the form of vivid, intrusive memories, flashbacks or nightmares. These are typically accompanied by strong or overwhelming emotions, particularly fear or horror, and strong physical sensations.
  • Avoidance of thoughts and memories of the event or events, or avoidance of activities situations, or people reminiscent of the event or events; and Persistent perceptions of heightened current threat for example as indicated by hypervigilance or an enhanced startle reaction to stimuli such as unexpected noises.
  • The symptoms persist for at least several weeks and cause significant impairment in personal, family, social, educational, occupational or other important areas of functioning” (WHO ICD-11).

This definition aims to reduce the overlap with other diagnoses while still being clinically useful.


Crocq, M. A., & Crocq, L. (2000). From shell shock and war neurosis to posttraumatic stress disorder: A history of psychotraumatology. Dialogues in Clinical Neuroscience, 2(1), 47-55. Retrieved from

Pitman, R. K. (2013). A Brief Nosological History of PTSD. Journal of Traumatic Stress Disorders & Treatment, 2(1).

World Health Organisation. (2019). International Statistical Classification of Diseases and Related Health Problems (11th Revision).

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Post-Traumatic Stress Disorder (PTSD) in the Global Context

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