As the name suggests, Post Traumatic Stress Disorder - or PTSD - is a type of trauma occurring after, post, a stressful, traumatic event. Any individual who experiences a traumatic event can go on to develop PTSD, and may require PTSD treatment in order to work through the disorder. The defining characteristic of a traumatic event is its capacity to provoke fear or helplessness, typically, but not exclusively, in response to a life-threatening event. Examples of traumatic events can include assaults, road accidents, child or domestic abuse, war, or acts of terrorism.
Most people exposed to traumatic events experience some form of short-term distress. Anyone involved in such an event will naturally experience a set of reactions. These include feeling on edge, having trouble sleeping, feeling detached from the experience, or having upsetting memories of the event. These are normal reactions to what is an abnormal situation.  However, not everyone who experiences a traumatic event will go on to develop PTSD. Over time, for most people, these natural reactions will fade. If they linger, however, lasting more than a few months, they may be considered symptomatic. In this case, an individual could be diagnosed with PTSD, and could benefit from post traumatic stress disorder treatment.