Oppositional Defiance Disorder (ODD) is not the only disorder linked to defiant behavior. It can stem from a number of underlying factors you may not have considered: medical and mental health issues can play a role in a child's behavior, and taking a close look at these possibilities can help you better understand your child and meet his needs. Some of these issues have simple solutions; others don't, but no matter what the issue, if your child has another problem he can't define for you, you'll be on a much better track once you have an honest understanding of what you're dealing with.