It is estimated that about 1 in 100 people are psychopaths, but although many violent offenders fall into this category it does not mean all psychopaths will be violent. Nor does it mean all violent people are psychopaths. Is the tendency towards psychopathic behaviour something that people are born with, or is it something caused by our upbringing? Find out about the indicative behaviours doctors look out for when making a diagnosis of psychopathy.