Synonyms: Post-traumatic stress disorder, Shell shock

Medical Specialties: Family practice, Psychiatry

Clinical Definition

PTSD, or post-traumatic stress disorder, is classified as an anxiety disorder by the American Psychiatric Association. It is triggered by a severe traumatic event, which causes fear of injury or death. The exact reason why some individuals develop PTSD is not known. The theory is an adrenaline response during the initial trauma may lead to a change in neurological patterns in the brain. This creates a hypersensitive response, even well after the trauma is past.

In Our Own Words

Post-traumatic stress disorder, or PTSD, is a psychiatric condition, which can develop as a result of a severe traumatic event. PTSD is different from a normal reaction to a traumatic incident. While anxiety, depression, nightmares and flashbacks may occur after a significant trauma, with PTSD, symptoms continue long after the event has past.


It is not clear why some people develop PTSD after a severe traumatic event. The biological response, which occurs during the fight or flight response, may change brain chemistry and lead to PTSD in some people. People with PTSD may experience emotional distress if they are in a situation that reminds them of the past trauma they experienced.

Relevant Conditions
  • Psychological trauma
Side Effects
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  • National Alliance on Mental Illness. "What is Post Traumatic Stress Disorder?" Accessed October 2013.
  • Ohio State University Wexner Medical Center. "Post-Traumatic Stress Disorder." Accessed October 2013.
  • University of Pennsylvania: Perelman School of Medicine. "Post-Traumatic Stress Disorder." Accessed October 2013.
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