Oppositional defiant disorder (ODD) is a persistent behavioural pattern of anger or irritability; argumentative, defiant behaviour toward authority figures; and vindictiveness lasting at least 6 months. In some children with ODD, these behaviours are only in evidence in one setting – usually at home. In more severe cases, they occur in multiple settings. For a diagnosis of ODD, the frequency and intensity of these behaviours must be outside the typical range for the child’s gender, culture and developmental level.