Children and teenagers will always be prone to periods of irritability and defiance, where rebelling against their parents or refusing to follow rules, whether at home or at school, can actually be part of healthy development into adulthood. ODD is diagnosed when a pattern of frequent and severe disruptive mood and defiant behaviour, against either peers or authority figures, is negatively affecting a young person's relationships and social interactions with many people around them, as well as being outside the norm for their age group.

ODD is a behavioural disorder, usually diagnosed in childhood, that is characterised by uncooperative, defiant, negative, irritable and annoying behaviours towards parents, peers, teachers and other authority figures.  Many children, particularly adolescents, can be oppositional.  However the oppositionality of ODD persists despite reasonable parenting strategies.