Correlation

Saw an Italian film this weekend called Il Postino. It's set on an island off the peninsula; presumably Sicily. One of the main issues that ran through the film was the lack of fresh water from which the island suffers.
I have often thought that there my be a correlation between places where there is no fresh flowing clean water and madness. I know I would not be of sound mind or body were I to rely on water coming in from the outside.
Hell! I live in Los Angeles where I'm not even too crazy about the municipal water that IS supposed to be healthy enough for us to drink without any sort of conditioning.
I wonder why there aren't plants set up to remove the salt from sea water. How difficult could it be?
Oh well... a nice place to visit but I wouldn't want to live there.