Disruptive behavior disorders are among the easiest to identify of all coexisting conditions because they involve behaviors that are readily seen such as temper tantrums, physical aggression such as attacking other children, excessive argumentativeness, stealing, and other forms of defiance or resistance to authority. These disorders, which include ODD and CD, often first attract notice when they interfere with school performance or family and peer relationships, and frequently intensify over time.

Behaviors typical of disruptive behavior disorders can closely resemble ADHD—particularly where impulsivity and hyperactivity are involved—but ADHD, ODD, and CD are considered separate conditions that can occur independently. About one third of all children with ADHD have coexisting ODD, and up to one quarter have coexisting CD. Children with both conditions tend to have more difficult lives than those with ADHD alone because their defiant behavior leads to so many conflicts with adults and others with whom they interact.
Early identification and treatment may, however, increase the chances that your child can learn to control these behaviors.