Yes, I probably have Social Anxiety Disorder from when I was a primary school boy. At least my parents put me then into play therapy for shyness.
I talked only with some people I was familiar with.
Now I have spend decades in nearly complete social isolation, only talking once in 6 weeks or so with my mother on the telephone and for the rest with nobody else.
There were times between in which I interacted more with people and when I am with people now I say much more than I did at secondary school.
Earlier I thought the problem was just me being shy, but now problems are much more complicated. I believe that I behave in a way strange which is not seen as shyness. I tried around 1987 to get rid of my shyness with Rational Emotional Self Therapy and ended up not so shy as before, but behaving very strange instead: Yes you shouldn’t bother so much about what people think of you.
Later there came also other reasons to isolate myself. I became clinically schizophrenic (by self-diagnosis) and couldn't stand to be around others anymore because of the terrible impression I thought to make on others. I thought that when I thought in words I compulsively spoke it out with closed mouth in such a way that others could hear it. I had the idea that I was constantly making audible remarks on everyone and that made me very uncomfortable and gave me the idea that I did something wrong.
Now I can get that idea out of my head when I want, I can stand people a little bit more. Twice a year I go to a family dinner and a few months ago I started frequenting a sport club. At first everyone did very strange towards me probably because of excessive gossip (telling around that I am crazy and/or a child molester) and some imperfections in my non-verbal behavior. I have decided not to run away, but stay there so I become more accustomed to people around me and I hope they also stop behaving stupid.