People exposed to a traumatic incident will most likely develop some of the symptoms of PTSD. These symptoms can be very long lasting and severe. Why PTSD develops is currently being studied. Biological, psychological and social factors affect the development of PTSD | People exposed to a traumatic incident will most likely develop some of the symptoms of PTSD. These symptoms can be very long lasting and severe. Why PTSD develops is currently being studied. Biological, psychological and social factors affect the development of PTSD |