My DS used to hold his breath when he was little. He would hold it until he passed out. It started happening when he fell and got hurt. He kept doing it more and more often. He was about 2 when he started it. I of course called the pediatrician and they said it was fine as long as he wasn't going in to a convulsion. Eventually he started doing it when he got yelled out. Dr said it was for attention and to ignore it. He did this for about 6 months. I was never really convinced that it was really ok until he did it in front of the Dr when he got a shot. The Dr's only comment was we have a stubborn one here.