Kids with ADHD sometimes exhibit oppositional behavior. This can be due to problems with emotion regulation, impulsivity, inconsistent or harsh parenting or because your child feels overwhelmed, helpless or criticized. Talk to your doctor about your child's oppositionality. You may need to adjust medications or seek behavior therapy to help with your child's ADHD symptoms. Once these symptoms are better controlled, you might see a reduction in oppositionality. If your child's behavior worsens around the same time each day, your child's medication may be wearing off and you may need an afternoon dose.