When is a psycho not a psycho?

I watched Alfred Hitchcock's 'Psycho' for the first time in my life tonight. It's one of those films that everyone in the western world and beyond seems to have seen long ago during some kind of shared cinematic childhood experience. Well, at 26 years of age I watched it and enjoyed it.Of course its resonance in popular culture meant that I was aware of the famous shower scene and the fact that Norman Bates and his mother are one and the same person before I sat down to watch it. Nevertheless the eery score, the palpable tension and some great performances all made it highly enjoyable to watch.It got me thinking though. Norman Bates is obviously deranged. He is not mentally competent. He is, for the wont of a better word, a psycho. Can Master Bates (the 13 year old in me couldn't resist) therefore be culpable for his psychotic killing spree? Essentially he is a sick person who, without the mental illness would not be driven to commit such horrendous deeds. Is it fair to hate him or should we feel sorry for him?Personally, I think, apart from very limited circumstances of say self-defence or coming under extreme duress, you have to be deranged to commit murder.The most infamous serial killers hacked their victims to pieces. To state the obvious that's not normal behaviour and to take someone's life for the fun of it is in itself psychotic. It raises a point that the majority of murderers are psychotically afflicted in some ways. Should more emphasis be put on correcting their behaviour and trying to heal them or should we lock them up and throw away the key?I don't think there's a definitive answer. A little bit of both is probably just what the doctor (a psychiatrist of course) ordered.Obviously most offenders commit murder and try to get away with. That means on some level they know what they have done is wrong and are culpable and should be faced with the lock with no key scenario. Then again the fact that they can kill someone in cold blood surely means that they are not all there. Any right-minded thinking person could never do that. I'd rather believe that than believe that people can kill in cold blood and be completely in control of their senses. To me an individual like that is a scarier prospect than all of Hitchcock's horrors put together.