Please note, I am not a T as well or have any mental health training. Just been living with this for most of my life.

If it causes you to have the symptoms of PTSD, then there is a good chance you or others have it or experiencing something similar. The trauma doesn't have to be anything specific, just anything traumatic that effects you after the incident has already past. If you are thinking about it when you don't want to, having increased anxiety, being always on guard or paranoid. If you are showing any of those symptoms plus a few others, then you could be experiencing PTSD.

From mayo clinic:
Post-traumatic stress disorder (PTSD) is a mental health condition that's triggered by a terrifying event — either experiencing it or witnessing it. Symptoms may include flashbacks, nightmares and severe anxiety, as well as uncontrollable thoughts about the event.

Doesn't need to be a single event or any kind of specific incident. It could be any event, as long as it was traumatizing to that person. Everyone finds different things traumatizing and reacts to them differently.