Try not to be so hard on yourself. You talked about feeling naive. You're right--it's hindsight that makes you think you should have seen something. Knowledge = empowerment, so now you're better able to understand. However, when all you had to go on were strange actions and emotional outbursts, how could you possibly understand what was going on? I'm pursuing a degree in psychology and then will go on for my M.A. in counseling. If I was in your position, it could be possible for me to spot such a thing, but that's because that sort of thing is what I'm trained to do. You're not a mental health professional...you're a person who loves her, and those things can prevent you from understanding what's going on. You're not supposed to be able to pull a diagnosis out of all the crazy things that happen. You're too personally involved to do that, anyway. That's why they don't let mental health professionals counsel their own families--because we can't be objective!
I'm glad my reply helped you to understand some of the reasons for the things that have been happening. I hope it helped you grasp the fact that you're not alone. As for your communication, it's great that you're willing to let her share at her own pace. That is essential, because there are times when people press for answers to sensitive issues, and that just makes us retreat further into ourselves as a method of protection. One thing you might consider doing is: when there is a situation in which you think a PTSD thing is involved, make note of it. Then, when things are calm again, you might gently ask her if she wants to talk about it.
You could say something like: "Before you got angry about ___, I noticed that you seemed to be feeling ___. Do you want to talk about it?" Phrasing it in a manner like that helps her to see that you're concerned and recognize it, but you're not demanding an answer. See, there are a lot of times when we just seem to snap, and if we take the time to figure out a possible reason, it can be attributed to some kind of stress. Remember that stress is defined differently for us. For example, last year, there were a lot of things going on with school, and I was asked to go to my cousin's wedding, where I would see some of the abusers.
One day, I experienced a memory or flashback (I can't remember which one), and I couldn't seem to let go of those emotions. For the rest of the week, I just felt sad and worthless, and it was all triggered by that memory. By the end of the week, I found out that one of my roommates had stolen some of my stuff, and I confronted her calmly. She got defensive and started blaming me and some others. She wouldn't even let me finish my explanation of what had happened and what I was feeling. I left the room with the increased sense that I was worthless. Then I went back to her and just....exploded. I can't remember the last time I did that--not counting that experience. She still wouldn't listen, so when I got back to my dorm room, I started thinking about an unhealthy coping skill. I initially got something out so I could deal with it in a healthy manner. Then I thought, "If I'm not worth three minutes of this girl's time, and if the abusers didn't care if I died in a fire, then it's not worth my time to struggle with this and do something healthy." So....I got things out so I could engage in the unhealthy coping skill. See, none of this is really logical. It was all touched off by one memory, and then as things built, PTSD symptoms worsened, and it culminated in this thing with my roommate and the choice for me to do something unhealthy to my body.
In typical people, none of things would have progressed as far as they did. You know, when one person told me just to let it go, I really wanted to punch her in the face. And no, I would and never have done that; it just made me so angry that she thought I could just let it go! These things all triggered reminders of the repetitive trauma in one way or another, which is why they went as far as they did. My point in all of this is that there is likely something behind these seemingly insignificant things that make her just fly off the handle or whatever it is that happens. You can take the opportunities--after things have settled down, of course--to ask her about her PTSD. This post is certainly long enough! If you would like, I can give you an idea of some questions to ask her so she's less likely to get defensive. Remember that her words and actions are still her choices but that they are highly likely to be related to her PTSD and not aimed at you. If/when she does get defensive about a perceived slight, try not to take it personally, but at the same time, recognize it because it is what she's feeling. Does this make sense, or is it just way confusing? If you want examples of how you can respond to her, I would be happy to post them--a part of the training I just finished in school is directly related to dealing with crisis and trauma.
NativeRose