Deviation from social norms is used in clinical practice. For example, the key defining characteristic of antisocial personality disorder is the failure to conform to culturally acceptable ethical behaviour i.e. recklessness, aggression, violating the rights of others and deceitfulness. These signs of the disorder are all deviations from social norms. Such norms also play a part in the diagnosis of schizoptypal personality disorder, where the term 'strange' is used to characterise the thinking, behaviour and appearance of people with the disorder.