It can also be caused by a head injury Maggie. They all share damage, lesions or abnormal function in the prefrontal cortex. Fallon looked at brain scans and found that scans of serial killers ALL had a problem in this area - in looking at a scan of his own, he realised that he also had this problem. It went a long way to explain why he engages in risky behaviours - his family weren't shocked by the revelation.
I remember reading it Caroline. Think it was in the Observer?
I know there are different grades of psychopaths and most never kill but they will show a lack of empathy and/or a lack of fear.
Winston Churchill was very possibly a psychopath to some degree. He wasn't a very successful peacetime politician but came into his own as a war leader. He possessed the right qualities, you cannot be sentimental about loss of life of the enemy or those on your own side. The aim is to win at all costs.