How is “Complex PTSD” different from PTSD?

Have you come across the term “complex PTSD” in descriptions of clinical cases? From time to time, I see this term used by colleagues. Is “Complex PTSD” a specific diagnosis? If so, how exactly is it different from PTSD?

Complex PTSD does NOT simply mean a complicated case of posttraumatic stress disorder (PTSD). It means something very specific. I think it is worth a few minutes of our time to understand—briefly—what Complex PTSD is.