After years of being under-diagnosed, especially in military personnel, post-traumatic stress disorder (PTSD) is starting to come into the awareness of the medical community and the mainstream community as well. As the medical community learns more about this imbalance, there is more research on how it affects patients and how we can better recognize it and treat post-traumatic stress disorder.
The definition of PTSD is the development of certain symptoms following a mentally stressful event that involved actual death or the threat of death, serious injury, or a threat to oneself or others. These events can happen in any environment, however two of the most well-studied at this time are military personnel and people diagnosed with terminal illnesses, especially cancer.
Other scenarios that predispose a person to developing PTSD are having the experience of intense or long-lasting trauma, or being abused or neglected as a child.
https://www.empowher.com/posttraumatic-stress-disorder-ptsd/content/learning-more-about-post-traumatic-stress-disorder