New research shows psychopaths have a personality disorder that is widely misunderstood.
Researchers examining psychopathy have found that there is a lack of consensus among scientists about even the exact nature of the disorder.
One of the researchers says if it is not known exactly what psychopathy is, the treatment of psychopaths must be undertaken cautiously.
Devon Polaschek from Victoria University says a core component of psychopathy is emotional detachment, whereas some of the country's most severe criminals, labelled as psychopaths, are emotionally disturbed rather than detached.
She says that distinction needs to be investigated to help develop better treatments for criminals.