I sometimes avoid folks too, online and in real life. I don't feel required to reply to texts or posts. If someone persists in texting me, etc., I will kindly say that I am heading to bed for a nap, or whatever, so as to deter them. I think it is our right to communicate or not, as we wish. That is just my opinion.
I have to isolate too. I have a new 3d friend that I see almost every day, and it means I have to nap in the afternoon every day. I have to push myself to answer texts and calls since I am enjoying the friendship. Sometimes I can come on here and write a lot, but then I completely forget some people on here. Not that I want to, I just do. This is the hard part of PTSD for me. I want to have friends and be open, however it is a HUGE stress for me. I think I'm getting better with it, but I can't even tell. I'm just glad I have an intake appointment with my latest therapist in a few days.
Yes I have this same issue, and I mostly identify with the not responding to texts, or emails when it really would not take much time at all. And, I don't like it when people don't respond to my texts. If it's a business text, I respond. I just force myself to and I'm more motivated, because I don't want to "be bad," Yet sometimes there is such a block. Some of the block for me might be that I'm afraid I'll make a mistake in my what I say or choose to say. I can't trust myself, and the issue of not trusting myself ties into my ptsd in multiple and complex ways. The bottom line is that things I've said or done resulted in traumatic episodes beginning early in life and carrying onward.
The other issue with the not responding, or avoiding answering texts,, or forum messages, or emails and the like is related to this:
My brain has completely shut down on me many times. Sometimes it isn't shut down completely it's just sort of there and it's too hard to wrap my brain around it. I've wondered about the autism thing at times because sometimes I can't even respond to people, look them in the eye, when there are is too much stimulation in the room. However, i dont' think it's autism I think it is trauma brain, a type of dissociation. I can't break out of it easily and then people ask me if I'm ok, or they tell me I've suddenly become 'quiet" or "not there, " tonight is an example I was doing it again with a group of people I had met only a few days ago, and I saw one person looking at me repeatedly and I realized I had that "blank look" on my face and I was dissociating. I tried to perk up and smile and forced myself to look her in the eye. Boy, that was Hard to do. I just didn't feel connected and I did not want to feel connected to other people.