I was very overweight as a child and mocked for that as well, and my confidence levels were on the floor. In my case, I've noticed that general insecurity was what most likely led to speech insecurity. The very first time that OCD kicked in was when I was about 12-years-old, when I entered a bookstore and went to the medicine section and thought I had cancer. I obsessed about it to the point of actually going to the doctor and getting checked for it. Then I guess it was dormant for many years, and showed up again when I was about 15, after boarding school where I was picked on for a whole year. Then OCD really kicked in. After boarding school, I became a heavy pot smoker (due to the shit I put up with at school, I guess..) and took LSD a few times at around 16/17. Once I took a very heavy hit, and the stuttering was minimal after the effects wore off, but I was seriously obsessing about catching diseases, etc.. I had to live with the OCD - and still do - and take medication to keep it in check. I would rather stutter - OCD is a living hell.