Wow! A lot of great insight here folks. I appreciate it.

Pandora, I just wanted to be clear that I myself did not experience a trauma. I am asking from a carers perspective.

My GF with PTSD has completely withdrawn from me and I didn't know that she had it until after she put our relationship on hold saying she needs space to work through her demons. Her trauma was 13 years ago, but she just got out of a physically abusive marriage which I think has brought a lot of the issues back to the surface.

I want to help her, but of course I can't even tell her that I am researching this stuff and trying to find ways to help her because she wants her space. It's tough giving her that when we work together and see each other everyday.

Thank you all for your replies and I am looking forward to hearing more and understanding more.