I've known for a while I have symptoms that align with complex PTSD, as do many here, but it wasn't until researching some books online that I really understood how strong the connection is to DP. For those who are unaware of complex PTSD there's lots of posts on this site about it but in general here's a rundown courtesy of Wikipedia:
https://en.wikipedia.org/wiki/Complex_post-traumatic_stress_disorder
I would strongly encourage people on this site to closely examine themselves, their current situation as well as past emotional states in order to understand how they got here and whether their symptoms and life story align with complex PTSD. In my case it's quite clear that I've suffered from complex PTSD my whole life but that I tried desperately to ignore all the emotions and symptoms that consistently bubbled up throughout my lifetime until I couldn't ignore them anymore thanks to two episodes of DP-DR. It's my belief that DP-DR states are often the culmination of complex PTSD's effects on the brain -- at least this appears to be the case based on my own experience. And of course, this is why therapy is so crucial for coping with DP-DR. If you don't understand how you got to where you are you're bound to suffer from repeating episodes and make the same mistakes again.
