When a child voluntarily defacates or urinates on himself it's a psychological issue. It's seen in toddlers but the oposite effect, toddlers/preschoolers will hold thier poop in and get constapated because they dont want to stop what they are doing. They outgrow it. I suggest you seek help from a child psychologist.
My son is 11 and does the same thing only practically daily. He fights me to change his clothes too. I had him examined to rule out medical causation and there is nothing physically wrong. I am going to try metamucil. But this is just horrible. Trisha
My 8 year old ADHD boy has the exact same issues as you discuss. He has gone through pooping/peeing himself on and off now for the past year. He'll do it for a week or three, then it will stop for a couple months & out of the blue start again. He doesn't seem to mind walking around with loaded pants for hours unless we notice nor does he seem to notice it's happened. As you state, usually when he's playing a game or preoccupied with something. He also is more likely to do it a gramma's house, where he receives total coddling and very limited expectations. He wears pull-ups at night and pee's every night, but this seems like a different problem than daytime incidences. He has ADHD and is on Daytrana. We see his pediatrician regularly and he can't seem to figure it out. We did take him to an urologist who did an x-ray, but found no physical reason why it is happening. Curious if you have found anything out about your situation, or be able to give me any insight? Thanks so much!