Oppositional Defiant Disorder (ODD) is characterized by frequent and consistent periods of irritation or argumentation toward authority figures that typically begins in preschool years. The DSM-5 lists symptoms including angry/irritable mood, argumentative/defiant behavior, and vindictiveness that negatively impact various areas and last at least 6 months. While there is no single cause, potential factors include genetics, parenting styles, brain chemistry, and social environment. Treatment focuses on therapy that involves training for both the child and parents to improve relationships and behaviors.