I work at an answering service. We answer the phones after hours for doctors, government agencies, etc. Their are allot of nuts out there. Some of the more funny ones will call a dozen times a day. Sometimes the same nut(or telemarketer) will call several different places and not realize he is reaching the same place each time. This makes for some pretty hilarious situations.

About 9 out of 10 you can tell a nut by tone of voice even before he gets into his ravings. Don't know why - severe mental illness must do something to ones voice. Or else I am just recognizing the same voices calling again and again.

The person who calls in and sounds perfectly normal like you or I, has a perfectly rational conversation, and then says that he was abducted by aliens and told to kill the president is pretty rare. Most have a telling tone in their voice right from the start.

This kind of puzzles me, because if you actually visit a mental hospital, etc. there are allot of delusional people you can actually have a real conversation with for some time. Were it not for the setting, you never would have known that ya were talking to someone who has been commited for 5 years... etc. MOST of the seriously mentally ill look and talk like normal people MOST of the time. Even the severe cases that make it to the state hospitals. The movie "Girl Interupted" has a pretty good portrayal as I understand it (though I am no expert)

It must just be the ones that call that sound different....