One of the most difficult things I have ever had to do was to write down my trauma. Writing is powerful, powerful in a way the speaking just isn't. Writing lends a certain amount of permanency that no other medium does. Writing about my trauma was both painful and positive. The first time I had to write it all down was in a letter to the judge for my SSDI hearing. On the other end of it I did feel somehow lighter. It didn't last forever, but I found it a little less difficult to write when I launched this site, I was a bit at odds with myself putting it out for the world. But it was easier than that first time. So while I now advocate writing about trauma, it does need to be paced and at the right time.
Beyond writing about trauma we have all kinds of writing that can help. Journaling is known to reduce depression and is excellent at helping to pinpoint triggers and other events that may cause episodes.
If these aren't your kind of writing, write other things, stories, novels. I have several stories in the works. They may never be finished, but it isn't about publication. It is about a process that engages my brain in a way that keeps the bad from creeping into my thoughts.
Writing stories can also help to express things you simply can't in your day to day life. You can have fictional people doing the things you can't. You can enjoy a nearly perfect existance in the fictional world, allow yourself to unburden, and even learn about yourself.
I often write when I can feel things going sideways, it helps me get out of that state of mind, it also helps me reframe what is causing things to go sideways. Often I find the answer to issues during a writing session.
If you have PTSD try writing, in any form and see if it helps. I bet it will.